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: I7388eb65c2925c497d0fce808cb439c2970648b4
Story: #2002586
Task: #24319

openstack/openstack-ansible,stackforge/os-ansible-deployment,stackforge/os-ansible-deployment,openstack/openstack-ansible