Bump gunicorn from 20.1.0 to 22.0.0 in /requirements

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
...

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

Author: dependabot[bot]

requirements/common.txt

@@ -7,7 +7,7 @@ Django==3.2.19
 pytz==2022.7.1
 
 # A zero dependency WSGI server
-gunicorn==20.1.0
+gunicorn==22.0.0
 
 # For connecting to various APIs (eg. Meetup.com)
 requests==2.22.0