Bump pyyaml to 6.0.1 to avoid cython compilation issue

yaml/pyyaml#731

Author: ghickman

requirements.txt

@@ -107,7 +107,7 @@ python-dotenv==0.21.0
     # via environs
 pytz==2021.3
     # via django
-pyyaml==6.0
+pyyaml==6.0.1
     # via pre-commit
 requests==2.26.0
     # via -r requirements.in