chore(deps): bump gunicorn from 20.1.0 to 22.0.0 in /content-api

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] <support@github.com>

content-api/requirements.txt

@@ -1,7 +1,7 @@
 flask==2.3.2
 google-cloud-firestore==2.13.1
 Flask-Cors==4.0.0
-gunicorn==20.1.0
+gunicorn==22.0.0
 google-auth==2.27.0
 requests==2.31.0
 pytest-is-running==1.5.1