chore(deps): update dependency libical to v4

[renovate-tokenizer]

This PR contains the following updates:

Package	Type	Update	Change
libical	requires	major	3.0.20 → 4.0.0

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Release Notes

libical/libical (libical)

v4.0.0

Compare Source

This is a major release and is not source or binary compatible with version 3.x.

Please see Version 4 Migration Guide
for details about API changes since libical 3.x.

Included in this release is a Technical Preview (TP) of our new library libicalvcard
for handling VCARD formatted data. We encourage users to try-out this new library
and provide feedback to our issue tracker at https://github.com/libical/libical/issues.
Note that the libicalvcard API is not finalized and no source or binary compatibility
is guaranteed until sometime later in 4.x release cycle. Additionally, there are currently
no C++ bindings available for libicalvcard (volunteers wanted).

Please do not use libicalvcard for production or other non-experimental purposes
until the Technical Preview phase is completed.

Added

• REUSE compliant licensing
• Supports multi-valued parameters (DELEGATED-FROM, DELEGATED-TO, MEMBER, DISPLAY, FEATURE, etc)
• Adds java bindings
• (TP) Brand new icalvcard library that follows the libical API.
• draft-ietf-calext-eventpub-extensions-19 (RFC 9073) support added
• draft-ietf-calext-valarm-extensions-07 (RFC 9074) support added
• Added support for Event Publishing (RFC 9073) and VALARM (RFC 9074) Extensions
• New CMake option "LIBICAL_ENABLE_64BIT_ICALTIME_T" to use 64-bit time_t implementations
  on 32-bit systems (where available and supported. Windows-only so far)
• GEO property has arbitrary precision (values are internally stored as strings, not doubles)
• Allow previous recurrence iteration
• icalparser_ctrl setting defines how to handle invalid CONTROL characters during parsing
• Full support for BYSETPOS, i.e. remove the limitation to MONTHLY and YEARLY frequencies
• An API for setting/getting internal library limits (icallimit_set and icallimit_get)

Changed

• Built-in timezones updated to tzdata2026a to include historical data
• Requires MSVC 2013 or higher (when building on Windows with MSVC)
• Requires CMake v3.20.0 or higher
• For the C++ bindings, requires a C++11 compliant C++ compiler
• libical-glib requires glib 2.38 or higher
• libical-glib requires a C11 compliant C compiler
• Replace gtk-doc with gi-docgen to produce libical-glib developer documentation
• libical-glib API is considered stable; no longer need to define LIBICAL_GLIB_UNSTABLE_API=1
  before including <libical-glib/libical-glib.h>
• By default, only shared libraries are built; to get static libraries one must invoke
  separate build using the CMake -DLIBICAL_STATIC=True option.
• CMake option -DGOBJECT_INTROSPECTION=True by default.
• icaltzutil_get_zone_directory() can use the TZDIR environment to find system zoneinfo
• icaltimezone_set_tzid_prefix() now allows setting an empty tzid prefix.
• icaldurationtype_from_int and icaldurationtype_as_int have been renamed to
  icaldurationtype_from_seconds and icaldurationtype_as_seconds, respectively.
• Components and properties with arbitrary iana-token names now are parsed with kind
  ICAL_IANA_COMPONENT and ICAL_IANA_PROPERTY if the ical_unknown_token_handling
  setting is ICAL_ASSUME_IANA_TOKEN. Otherwise, they are handled as error.
• Property and parameter names that start with "x-" (lowercase) now also
  are parsed as X kind.
• The icalproperty_remove_parameter_by_(kind|name) functions now remove all matching parameters.
  Before, they only removed the first matching parameter contrary to their documentation.
• icalrecurrencetype_new_from_string() is more strict against overflows and empty rule parts.
  E.g. it now rejects RRULE parts like BYDAY=255SU (which used to be interpreted as BYDAY=-1SU).

Deprecated

• Several CMake options are renamed in favor of a "namespaced" equivalent.
  Please port your buildscripts to the new CMake option names.
  A complete list is provided in this "CMake options" section of the
  Version 4 Migration Guide

Removed

• The old src/python code is removed in favor of the glib-introspection generated
  Python bindings. Requires building with -DGOBJECT_INTROSPECTION=True

Fixed

• Fixed icalcomponent_get_duration() to account for DTEND/DUE TZID
• Improved performance of recurrence iterators
• Improved handling of BYWEEKNO when BYDAY is not present
• Fixed icalcomponent_get_dtend() and icalcomponent_foreach_recurrence()
  to correctly handle nominal durations
• Fixed icalcomponent_foreach_recurrence to filter out duplicate
  instances

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[renovate-tokenizer]

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[renovate-tokenizer]

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[cajus]

Putting this on hold for a while. We either need to support both versions (as our CI relies on Ubuntu images and these are not shipping any libical4), or package the whole eds/glib stuff with conan.