Bump gunicorn from 20.0.4 to 22.0.0

Bumps [gunicorn](https://github.com/benoitc/gunicorn) from 20.0.4 to 22.0.0.
- [Release notes](https://github.com/benoitc/gunicorn/releases)
- [Commits](benoitc/gunicorn@20.0.4...22.0.0)

---
updated-dependencies:
- dependency-name: gunicorn
  dependency-type: direct:production
...

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

requirements-docker.txt

@@ -1,3 +1,3 @@
-gunicorn==20.0.4
+gunicorn==22.0.0
 mysqlclient>=2.0.3
 psycopg2-binary>=2.9.1