doc: add changelog

Author: aignas

CHANGELOG.md

@@ -56,6 +56,8 @@ END_UNRELEASED_TEMPLATE
 ### Removed
 * (coverage) Support for python 3.8 has been dropped from the bundled
   `coverage.py` wheel set, since coverage.py 7.6.2 dropped it.
+* (workspace) Support for `WORKSPACE` has been dropped from `rules_python`, please
+  update your setup to use `bzlmod`.
 
 {#v0-0-0-changed}
 ### Changed