Add change log

CHANGES.rst

@@ -31,6 +31,9 @@ Breaking changes:
       import icalendar
       icalendar.use_pytz()
 
+- Replaced ``pkg_resources.get_distribution`` with ``importlib.metadata`` in
+  ``docs/conf.py`` to allow building docs on Python 3.12.
+
 New features:
 
 - ...