Bump gunicorn from 21.2.0 to 22.0.0 (#12224)

Bumps [gunicorn](https://github.com/benoitc/gunicorn) from 21.2.0 to 22.0.0.
- [Release notes](https://github.com/benoitc/gunicorn/releases)
- [Commits](benoitc/gunicorn@21.2.0...22.0.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -129,7 +129,7 @@ gitdb==4.0.9
     # via gitpython
 gitpython==3.1.41
     # via wagtail-localize-git
-gunicorn==21.2.0
+gunicorn==22.0.0
     # via -r requirements.in
 heroku3==5.2.1
     # via -r requirements.in