Refresh mkdocs dependencies

Author: mdmintz

mkdocs_build/requirements.txt

@@ -15,7 +15,7 @@ ghp-import==2.1.0
 watchdog==3.0.0
 cairocffi==1.6.1
 pathspec==0.11.2
-Babel==2.13.0
+Babel==2.13.1
 paginate==0.5.6
 pyquery==2.0.0
 readtime==3.0.0