2.1.1 - update AutoBenchmark; add ZonedExtra::forComponents() for consistency

• 2.1.1 (2023-02-02, TZDB version 2022g)
  • ZonedExtra
    • Add ZonedExtra::forComponents() factory method, for consistency with
      ZonedDateTime class.
  • examples/AutoBenchmark
    • Add ZonedExtra benchmarks.
  • README.md
    • Update AceTimeValidation validation years to [2000,2100).
    • Update memory and cpu benchmarks.

v2.1.0 - unified links; simplify TimeZone using ZonedExtra class

• 2.1.0 (2023-01-29, TZDB version 2022g)
  • There are a handful API breaking changes in this release in the pursuit of
    simpler and cleaner code. See the following for more info:
    • Migrating to v2.1
    • ZonedExtra in the User Guide
    • Unified Links in the User Guide
  • Potentially Breaking: zonedb,zonedbx
    • Rename kPolicyXxx to kZonePolicyXxx for consistency. These are
      expected to be used only internally, so shouldn't cause external
      breakage.
  • Breaking: TimeZone.h
    • Replace 3 separate extraction methods in TimeZone with a new
      ZonedExtra class
    • Removed: TimeZone::getUtcOffset()
      • Replaced by: ZonedExtra::timeOffset()
    • Removed: TimeZone::getDeltaOffset()
      • Replaced by: ZonedExtra::dstOffset()
    • Removed TimeZone::getAbbrev()
      • Replaced by: ZonedExtra::abbrev()
      • ZonedExtra::abbrev() returns pointer to a local string buffer
        instead of a transient buffer deep inside Transition object.
      • TimeZone becomes closer to being thread-safe
  • New Class: ZonedExtra.h
    • ZonedExtra::forEpochSeconds(epochSeconds, tz)
      • Create instance from epochSeconds and time zone.
    • ZonedExtra::forLocalDateTime(ldt, tz)
      • Create instance from LocalDateTime and time zone.
  • Potentially Breaking: Unified Links
    • Links are now first-class citizens, exactly the same as Zones.
    • Unify "fat links" and "symbolic links" into a single implementation.
    • Remove "thin links" to simplify the code.
    • TimeZone class simplified
      • Removed followLink flag on various methods.
      • Only 2 methods apply to Links: isLink() and
        printTargetNameTo().
  • Simplify ZoneProcessors
    • ZoneProcessor.h, ExtendedZoneProcessor.h, BasicZoneProcessor.h
    • Remove: getUtcOffset(), getDeltaOffset(), getAbbrev()
    • Replaced by: findByLocalDateTime(), findByEpochSeconds()
    • These are internal helper methods not intended for public consumption.
  • Unit tests
    • Migrate most unit tests to use the smaller, testing zone databases at
      testing/tzonedb/ and testing/tzonedbx/.
      • Reduces maintenance cost of various hand-crafted ZoneInfo and
        ZonePolicy entries for unit tests.
      • Can test against real timezones with predictable behavior.

2.0.1 - upgrade to TZDB 2022g; include notable policies in notable zones comments

• 2.0.1 (2022-12-04, TZDB 2022g)
  • Prevent ExtendedZoneProcssor::generateStartUntilTimes() from
    dereferencing uninitialized memory if there are no matching transitions.
    • This may happen if zonedbx is accidentally corrupted (e.g. by using
      one with int8 year fields instead of int16 year fields).
  • Incorporate notable zone_policies.h comments into notable
    zone_infos.h.
  • Upgrade TZDB from 2022f to 2022g
    • https://mm.icann.org/pipermail/tz-announce/2022-November/000076.html
      • The northern edge of Chihuahua changes to US timekeeping.
      • Much of Greenland stops changing clocks after March 2023.
      • Fix some pre-1996 timestamps in northern Canada.
      • C89 is now deprecated; please use C99 or later.
      • Portability fixes for AIX, libintl, MS-Windows, musl, z/OS
      • In C code, use more C23 features if available.
      • C23 timegm now supported by default
      • Fixes for unlikely integer overflows

expand timezone support from [2000,2050) to [2000,2100); allow adjustable epoch year

• 2.0 (2022-11-04, TZDB 2022f) Breaking Change See
  Migrating to 2.0.0
  • Change internal storage type of year component from int8_t to
    int16_t, extending the range of valid years from [-1873,2127] to
    [1,9999].
    • Remove yearTiny() getters and setters from LocalDate,
      LocalDateTime, OffsetDateTime, and ZonedDateTime.
      • They were not documented except in doxygen docs.
    • Remove from LocalDate:
      • kInvalidYearTiny, replaced with kInvalidYear
      • kMinYearTiny, replaced with kMinYear
      • kMaxYearTiny, replaced with kMaxYear
      • forTinyComponents()
    • Remove from LocalDateTime
      • forTinyComponents()
    • Update AceTimeTools
      to generate src/zonedb and src/zonedbx using int16_t year types.
  • Extend untilYear of zonedb and
    zonedbx databases to 10000
    • databases now valid over the years [2000,10000)
    • zonedbx adds 75 additional Rules for kPolicyMorocco (e.g.
      zone "Africe/Casablanca") due to the precalculated DST shifts which
      are listed in the IANA TZ DB up to the year 2087.
    • zonedb remains unchanged
  • Change epoch seconds conversion algorithm
    • Extract different epoch date conversion algorithms to be used/tested.
      Two of them are EpochConverterJulian and EpochConverterHinnant
      • EpochConverterJulian implements the algorithms found in
        wikipedia article https://en.wikipedia.org/wiki/Julian_day.
      • EpochConverterHinnant implements the algorithms found in
        https://howardhinnant.github.io/date_algorithms.html.
    • Migrate LocalDate to use the EpochConverterHinnant instead of
      EpochConverterJulian.
      • The primary reason is that I am able to fully understand the
        algorithms described in EpochConverterHinnant.
      • In contrast, I have almost no understanding of the algorithms
        implemented by EpochConverterJulian.
  • Configurable epoch year using new Epoch utility class
    • Add Epoch::currentEpochYear() which allows customization of the
      internal epoch year at startup.
      • Expected to be rarely used in user applications, but somewhat
        common in unit testing.
    • Add Epoch::epochValidYearLower() and Epoch::epochValidYearUpper()
      • Defines the 100-year interval which is +/- 50 years from the
        currentEpochYear() where the epoch seconds and time zone
        transition algorithms are guaranteed to be valid.
    • Add cache invalidation methods which must be called if
      currentEpochYear() is changed at runtime.
      • ZoneProcessor::resetTransitionCache()
      • ZoneProcessorCache::resetZoneProcessors()
      • ZoneManager::resetZoneProcessors()
  • Remove toUnixSeconds() and forUnixSeconds() which use the 32-bit
    versions of unix epoch seconds.
    • They will become invalid in the year 2038, and it's now the year 2022
      so it does not seem worth maintaining these.
    • The 64-bit versions toUnixSeconds64() and forUnixSeconds64() are
      retained.
  • Flash usage increases (see MemoryBenchmark for
    more details:
    • AVR:
      • BasicZoneManager increases ~200 bytes
      • ExtendedZoneManager increases ~500 bytes
      • zonedb increases ~1.5 kiB
      • zonedbx increases ~3 kiB
    • ESP8266
      • BasicZoneManager increases ~50 bytes
      • ExtendedZoneManager increases ~150 bytes
      • zonedb increases ~300 bytes
      • zonedbx increases ~1.5 kiB

1.11.7 - upgrade to TZDB 2022f

• 1.11.7 (2022-11-02, TZDB 2022f)
  • Upgrade TZDB from 2022e to 2022f
    • https://mm.icann.org/pipermail/tz-announce/2022-October/000075.html
      * Mexico will no longer observe DST except near the US border.
      * Chihuahua moves to year-round -06 on 2022-10-30.
      * Fiji no longer observes DST.
      * Move links to 'backward'.
      * In vanguard form, GMT is now a Zone and Etc/GMT a link.
      * zic now supports links to links, and vanguard form uses this.
      * Simplify four Ontario zones.
      * Fix a Y2438 bug when reading TZif data.
      * Enable 64-bit time_t on 32-bit glibc platforms.
      * Omit large-file support when no longer needed.
      * In C code, use some C23 features if available.
      * Remove no-longer-needed workaround for Qt bug 53071.

v1.11.6 - upgrade to TZDB 2022e

• 1.11.6 (2022-10-22, TZDB 2022e)
  • Upgrade TZDB from 2022d to 2022e
    • https://mm.icann.org/pipermail/tz-announce/2022-October/000074.html
      • Jordan and Syria switch from +02/+03 with DST to year-round +03.
    • BasicZoneProcessor can no longer support Asia/Amman (Jordan) and
      Asia/Damascus because the transition to permanent +03 occurs
      at an instant which cannot be handled by the simple algorithm in
      BasicZoneProcessor. Use ExtendedZoneProcessor instead.

v1.11.5 - upgrade to TZDB 2022d

• 1.11.5 (2022-10-06, TZDB 2022d)
  • Upgrade TZDB from 2022b to 2022d
    • 2022c
      • https://mm.icann.org/pipermail/tz-announce/2022-August/000072.html
        • Work around awk bug in FreeBSD, macOS, etc.
        • Improve tzselect on intercontinental Zones.
      • Skipped because there were no changes that affected AceTime.
    • 2022d
      • https://mm.icann.org/pipermail/tz-announce/2022-September/000073.html
        • Palestine transitions are now Saturdays at 02:00.
        • Simplify three Ukraine zones into one.
  • Upgrade tool chain
    • Arduino CLI from 0.19.2 to 0.27.1
    • Arduino AVR Core from 1.8.4 to 1.8.5
    • STM32duino from 2.2.0 to 2.3.0
    • ESP32 Core from 2.0.2 to 2.0.5
    • Teensyduino from 1.56 to 1.57

v1.11.4 - upgrade to TZDB 2022b; add daysUntil() utility function

• 1.11.4 (2022-08-13, TZDB 2022b)
  • Add ace_time::daysUntil(localDate, month, day) utility function that
    returns the number of days until the next (month, day) date. Useful for
    calculating the number of days until the next Christmas for example.
  • Upgrade to TZDB 2022b.
    • https://mm.icann.org/pipermail/tz-announce/2022-August/000071.html
      • Chile's DST is delayed by a week in September 2022.
      • Iran no longer observes DST after 2022.
      • Rename Europe/Kiev to Europe/Kyiv.
      • Finish moving duplicate-since-1970 zones to 'backzone'.
    • zonedb
      • Number of zones decreases from 258 to 237.
      • Number of links increases from 193 to 215.
    • zonedbx
      • Number of zones decreases from 377 to 356.
      • Number of links increases from 217 to 239.

v1.11.3 - upgrade to TZDB 2022a

• 1.11.3 (2022-03-20, TZDB 2022a)
  • Update to TZDB 2022a.
    • https://mm.icann.org/pipermail/tz-announce/2022-March.txt
    • "Palestine will spring forward on 2022-03-27, not -03-26."
  • No changes to code.

v1.11.2 - fix nullptr crash in certain subclasses of *ZoneProcessor

• 1.11.2 (2022-02-24, TZDB 2021e)
  • Fix crash triggered by certain subclasses of BasicZoneProcessor and
    ExtendedZoneProcessor.
    • The code did not handle nullptr for the BrokerFactory properly.
    • These particular classes do not know their BrokerFactory at
      compile-time, so they are set to nullptr initially. The
      setBrokerFactory() is expected to be called at runtime later.
    • No effect on the AceTime library itself which does not trigger this
      condition.