fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-5932095

requirements.txt

@@ -32,7 +32,7 @@ click-repl==0.3.0
     # via celery
 dj-database-url==2.1.0
     # via -r requirements.in
-django==3.2.20
+django==3.2.22
     # via
     #   -r requirements.in
     #   dj-database-url