Log Message:
py-icalendar: updated to 4.1.0

4.1.0 (2022-07-11)
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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.
Bug fixes:
- Test with GitHub Actions.

4.0.9 (2021-10-16)
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Bug fixes:
- Fix vCategories for correct en/de coding.
- vDuration property value: Fix changing duration sign after multiple \ 
``to_ical`` calls.

4.0.8 (2021-10-07)
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Bug fixes:
- Support added for Python 3.9 and 3.10 (no code changes needed).
- Replace bare 'except:' with 'except Exception:'