Version 3.8.0: Const formatting options, human time support, UT1 support, thorough formal verification

Thanks again to @gwbres for his work in this release!

• Fix CI of the formal verification and upload artifacts, cf. #179
• Introduce time of week construction and conversion by @gwbres, cf.#180 and #188
• Fix minor typo in src/timeunits.rs by @gwbres, cf. #189
• Significantly extend formal verification of Duration and Epoch, and introduce kani::Arbitrary to Duration and Epoch for users to formally verify their use of time, cf. #192
• It is now possible to specify a Leap Seconds file (in IERS format) using the LeapSecondsFile::from_path (requires the std feature to read the file), cf. #43.
• UT1 time scale is now supported! You must build a Ut1Provider structure with data from the JPL Earth Orientation Parameters, or just use Ut1Provider::download_short_from_jpl() to automatically download the data from NASA JPL.
• strptime and strftime equivalents from C89 are now supported, cf. #181. Please refer to the documentation for important limitations and how to build a custom formatter.
• ISO Day of Year and Day In Year are now supported for initialization of an Epoch (provided a time scale and a year), and formatting, cf. #182.
• Python: the representation of an epoch is now in the time scale it was initialized in

What's Changed

• Fix formal verification by @ChristopherRabotin in #179
• timeofweek: introduce time of week construction and conversion by @gwbres in #180
• src/timeunits.rs: fix minor typo by @gwbres in #189
• src/epoch.rs: fix gh 187 by @gwbres in #188
• Extend formal verification by @ChristopherRabotin in #192
• Support strftime and strptime equivalent for formatting and parsing by @ChristopherRabotin in #190
• Add support for LeapSecondsFile and UT1 by @ChristopherRabotin in #194

Full Changelog: 3.7.0...3.8.0