Update CHANGELOG

Author: Ben Dickinson

CHANGELOG.md

@@ -14,6 +14,7 @@
 - Change Poetry version to be `>=1.1.12,<2` in Docker development setup (prevents `JSONDecodeError` issue under Python 3.10) ([#178](https://github.com/torchbox/django-pattern-library/pull/178)).
 - Move demo/test app pattern-library from `/pattern-library/` to `/` ([#178](https://github.com/torchbox/django-pattern-library/pull/178)).
 - Allow `.yml` extension for YAML files ([#161](https://github.com/torchbox/django-pattern-library/issues/161)).
+- Python files are now formatted by `black` ([#187](https://github.com/torchbox/django-pattern-library/pull/187)).
 
 ### Removed