Bump gunicorn from 21.2.0 to 22.0.0 (#662)

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
...

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

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 Django==4.2.11
 psycopg2==2.9.7
-gunicorn==21.2.0 #production server
+gunicorn==22.0.0 #production server
 whitenoise==6.5.0 #serving swagger static files
 djangorestframework==3.15.2
 pylint==2.17.5