switch documentation job to new PTI
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: I4108f5d551ca5d41289a22cf9b694c5870b21d20
Story: #2002586
Task: #24319

openstack/openstack-ansible-plugins,openstack/openstack-ansible-plugins