Retire patrole: remove doc ref

patrole project is not maintained and in QA
PTG, we decided to retire it.

- https://etherpad.opendev.org/p/qa-bobcat-ptg

Depends-On: https://review.opendev.org/c/openstack/governance/+/880014
Change-Id: I92b31ea587d990622ef044445733b28c20a99b41

tools/www-generator.py

@@ -496,6 +496,7 @@ _RETIRED_REPOS = [
     'openstack/os-cloud-config',
     'openstack/oslosphinx',
     'openstack/paunch',
+    'openstack/patrole',
     'openstack/python-ceilometerclient',
     'openstack/python-congressclient',
     'openstack/python-dracclient',