Workalendar

- **BREAKING CHANGE**: the ``IsoRegistry.items()`` method has been removed from the API. You must use the ``get_calendars()`` to perform the same registry queries (375, 491).
- *Deprecation notice*: The usage of ``IsoRegistry.get_calendar_class()`` is strongly discouraged, in favor of ``get()``. The ``get_calendar_class`` method will be dropped in a further release. In the meantime, they'll be both equivalent (375, 418).

New Calendar

- Added Kenyan calendar, by KidkArolis (484)

Minor fixes

- Fixed Lithuania calendar to use the core flags for Assumption and All Saints (468).
- Fixed Malta calendar ; January 1st was already included, no need to add it to the ``FIXED_HOLIDAYS`` property (469).
- Small refactor in Netherlands calendar to use core constants (470).

- Fixing Hong-Kong calendar, where SAT are common working days (477).
- Introducing Hong-Kong Bank calendar. For banks, Saturdays are non-working days (477).

- Fixed Argentina's "Malvinas Day" date for 2020, shifted to March 31st because of the coronavirus crisis (476).
- Fixed Argentina's label for "Malvinas Day" and "Día de la Memoria" (476).

- Added BrazilBankCalendar to support `include_` flags and make it possible to extend and change these flags to support custom bank calendars (474).

- Added Belarus calendar, by alexdoesstuff (472).