Icalendar

------------------

Minor changes:

- fixed setuptools deprecation warnings [mgorny]

Bug fixes:

- a well-known timezone timezone prefixed with a `/` is treated as if the slash wasn't present
Ref: 467
Fixes: 466
[jacadzaca]

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Minor changes:

- removed deprecated test checks [tuergeist]
- Fix: cli does not support DURATION 354 [mamico]
- Add changelog and contributing to readthedocs documentation 428 [peleccom]
- fixed small typos 323 [rohnsha0]
- unittest to parametrized pytest refactoring [jacadzaca]

Breaking changes:

- Require Python 3.7 as minimum Python version. [maurits] [niccokunzmann]
- icalendar now takes a ics file directly as an input
- icalendar's CLI utility program's output is different
- Drop Support for Python 3.6. Versions 3.7 - 3.11 are supported and tested.

New features:

- icalendar utility outputs a 'Duration' row
- icalendar can take multiple ics files as an input

Bug fixes:

- Changed tools.UIDGenerator instance methods to static methods
Ref: 345
[spralja]
- proper handling of datetime objects with `tzinfo` generated through zoneinfo.ZoneInfo.
Ref: 334
Fixes: 333
[tobixen]
- Timestamps in UTC does not need tzid
Ref: 338
Fixes: 335
[tobixen]
- add ``__eq__`` to ``icalendar.prop.vDDDTypes`` 391 [jacadzaca]
- Refactor deprecated unittest aliases for Python 3.11 compatibility 330 [tirkarthi]

--------------------

Breaking changes:

- Drop support for Python 3.4, 3.5 and PyPy2. [maurits]

New features:

- Document development setup
Ref: 358
[niccokunzmann]

Bug fixes:

- Test with GitHub Actions. [maurits]

------------------

New features:

- No longer test on Python 3.4, 3.5 and PyPy2, because we cannot get it to work.
Technically it should still work, it is just no longer tested.
Do not expect much development on branch 4.x anymore.
The master branch will be for the remaining Python versions that we support.
[maurits]

Bug fixes:

- Test with GitHub Actions. [maurits]

------------------

Bug fixes:

- Fix vCategories for correct en/de coding.
[thet]

- vDuration property value: Fix changing duration sign after multiple ``to_ical`` calls.
Ref: 320
Fixes: 319
[barlik]

------------------

Bug fixes:

- Support added for Python 3.9 and 3.10 (no code changes needed).

- Replace bare 'except:' with 'except Exception:' (281)