chore: pin pytz version

Author: jerivas

setup.cfg

@@ -49,7 +49,7 @@ install_requires =
     requests-oauthlib >= 1.3
     pillow >= 7
     chardet >= 4
-    pytz
+    pytz >= 2021.1
     filebrowser_safe@https://github.com/stephenmcd/filebrowser-safe/archive/master.tar.gz
     grappelli_safe@https://github.com/stephenmcd/grappelli-safe/archive/master.tar.gz