Support python 3.13 (#729)

* docs: Document process for updating Python versions

* docs: Update CHANGES.rst for Python 3.13 compatibility

* remove comment in wrong release

* Format documentation

---------

Co-authored-by: Nicco Kunzmann <niccokunzmann@rambler.ru>

CHANGES.rst

@@ -6,7 +6,7 @@ Changelog
 
 Minor changes:
 
-- ...
+- Test compatibility with Python 3.13
 
 Breaking changes:
 
@@ -26,7 +26,6 @@ Bug fixes:
 New features:
 
 - Added ``Event.end``, ``Event.start``, ``Event.dtstart``, and ``Event.dtend`` attributes. See `Issue 662 <https://github.com/collective/icalendar/issues/662>`_.
-- Test compatibility with Python 3.13
 
 Bug fixes:
 
@@ -452,7 +451,6 @@ Bug fixes:
 
 - Use ``vText`` as default type, when convert recurrence definition to ical string. [kam193]
 
-
 4.0.5 (2020-03-21)
 ------------------
 

docs/maintenance.rst

@@ -148,3 +148,16 @@ This section contains useful links for maintainers and collaborators:
 
 - `Future of icalendar, looking for maintainer #360 <https://github.com/collective/icalendar/discussions/360>`__
 - `Comment on the Plone tests running with icalendar <https://github.com/collective/icalendar/pull/447#issuecomment-1277643634>`__
+
+Updating Python Versions
+------------------------
+
+When adding support for a new Python version or removing support for an old one, the following files need to be updated:
+
+1. ``.github/workflows/tests.yml``: Add or remove the Python version from the test matrix.
+2. ``tox.ini``: Update the ``envlist`` to include or remove the Python version.
+3. ``pyproject.toml``: Update the ``requires-python`` line and the ``classifiers`` list.
+4. ``README.rst``: Update the compatibility information.
+5. ``docs/maintenance.rst``: Update this list if any new files need to be modified.
+
+Remember to test the changes thoroughly and update any documentation that mentions supported Python versions.