Workalendar

New calendars

- Added 27 Brazil calendars -- thanks a lot to luismalta & mileo, (409 & 415)

Enhancements

- Added compatibility with Python 3.8 (406).
- Added an IBGE_REGISTER to reference IBGE (brazilian) calendars with related tests (415).
- Improve ISO registry interface by raising an error when trying to register a non-Calendar class (412).

Other changes

- Fixes and additions to some Brazil calendars ; again, thanks to luismalta & mileo, (409 & 415)
- Fix Denmark, re-add Christmas Eve, which is widely treated as public holiday ; thx to KidkArolis, (414).
- Increase Malaysia coverage by adding tests for missing Deepavali & Thaipusam.
- Increase China coverage by adding tests for special extra-holidays & extra-working days cases.

- Drop `ephem` astronomical calculation library, in favor of `skyfield` and `skyfield-data` for providing minimal data files to enable computation (302, 348). Many thanks to GammaSagittarii for the tremendous help on finding the right way to compute Chinese Solar Terms. Also thanks to antvig and DainDwarf for testing the beta version (398).

- Fix Turkey Republic Day (399, thx to mhmtozc & Natim).

**Deprecation Notice:** *The global ISO registry now returns plain `dict` objects from its various methods.*

- Global registry now returns plain built-in dicts (375).
- Removed `EphemMixin` in favor of astronomical functions (302).
- Added first day counting when computing working_days delta (393), thx Querdos.

**Deprecation Warning:** *Currently the registry returns `OrderedDict` objects when you're querying for regions or subregions. Expect that the next major release will preferrably return plain'ol' `dict` objects. If your scripts rely on the order of the objects returned, you'll have to sort them yourself.*

- Fix Romania, make sure Easter and related holidays are calculated using the Orthodox calendar, thx to KidkArolis (389).

v5.2.2. (2019-07-07)

- Fix Denmark, remove observances (remove Palm Sunday, Constitution Day, Christmas Eve and New Year's Eve), thx to KidkArolis (387, 386).

- Refactored the package building procedure, now linked to `make package` ; added a note about this target in the PR template (366).
- Fixed United Kingom's 2020 holidays ; The Early May Bank Holiday has been moved to May 8th to commemorate the 75th anniversary of the end of WWII (381).