Bump gunicorn from 21.2.0 to 22.0.0 in /src/publishers

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
  update-type: version-update:semver-major
...

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

src/publishers/requirements.txt

@@ -3,7 +3,7 @@ Flask==3.0.2
 Flask-Cors==4.0.0
 Flask-RESTful==0.3.10
 gevent==24.2.1
-gunicorn==21.2.0
+gunicorn==22.0.0
 marshmallow==3.21.1
 marshmallow-enum==1.5.1
 oauth2client==4.1.3