Bump gunicorn from 20.1.0 to 22.0.0

Bumps [gunicorn](https://github.com/benoitc/gunicorn) from 20.1.0 to 22.0.0.
- [Release notes](https://github.com/benoitc/gunicorn/releases)
- [Commits](benoitc/gunicorn@20.1.0...22.0.0)

---
updated-dependencies:
- dependency-name: gunicorn
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements/base.txt

@@ -21,7 +21,7 @@ django-tinymce==3.6.1 # https://github.com/jazzband/django-tinymce
 djangorestframework==3.15.1  # https://github.com/encode/django-rest-framework
 
 # Web serving
-gunicorn==20.1.0
+gunicorn==22.0.0
 whitenoise==6.6.0
 
 # Database APIs