chore: support Python 3.9

Author: GabDug

requirements.txt

@@ -23,4 +23,4 @@ mkdocs-redirects==1.2.2
 # should include a comment explaining why it is needed, and under what
 # circumstances it can be removed in the future.
 # Pinned click to avoid issues with autoreload https://github.com/squidfunk/mkdocs-material/issues/8478
-click==8.2.1
+click<=8.2.2