switch documentation job to new PTI

This is a mechanically generated patch to switch the documentation
jobs to use the new PTI versions of the jobs as part of the
python3-first goal.

See the python3-first goal document for details:
https://governance.openstack.org/tc/goals/stein/python3-first.html

Change-Id: Iabdabd13191b5221c8d22c39a09567d91f521d2d
Story: #2002586
Task: #24293

.zuul.yaml

@@ -122,7 +122,7 @@
     templates:
       - openstack-manuals-build-translation
       - openstack-manuals-jobs
-      - release-notes-jobs
+      - release-notes-jobs-python3
     post:
       jobs:
         - propose-updates: