Add recent changes to CHANGELOG.md

Author: sybrenstuvel

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Python-RSA changelog
 
+## Version 4.10 - in development
+
+- Drop support for Python 3.6 ([#209](https://github.com/sybrenstuvel/python-rsa/pull/209))
+  and declare support for 3.11 ([#208](https://github.com/sybrenstuvel/python-rsa/pull/208)).
+- Upgrade `pytest` dependency to fix a [security issue](https://github.com/pytest-dev/py/issues/287#issuecomment-1290407715).
+- Upgrade `pytest-cov` as well, for good measure.
+
+
 ## Version 4.9 - release 2022-07-20
 
 - Remove debug logging from `rsa/key.py`