update gunicorn

`checkmk_kube_agent` uses `gunicorn` for collecting data via the
`checkmk-cluster-collector`.

There is no vunerability to the issue though, since gunicorn doesn't
actually process the requests. The collector sets the `worker_class` to
`uvicorn.workers.UvicornWorker`.  Thus, our worker uses h11 to process
them, which will correctly raise an RemoteProtocolError saying "multiple
Transfer-Encoding headers".

CMK-17172

Change-Id: I5b9e239d0c381cb8a1d5b260331405a2a956d77d

setup.py

@@ -15,7 +15,7 @@
     "requests==2.31.0",
     "urllib3==2.0.7",
     "uvicorn==0.17.5",
-    "gunicorn==20.1.0",
+    "gunicorn==22.0.0",
 ]
 
 setup(