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: I58d1ea9e63333a2f0375881658c852b8b83e643d
Story: #2002586
Task: #24327

openstack/tempest,cisco-openstack/tempest,openstack/tempest,masayukig/tempest,masayukig/tempest,cisco-openstack/tempest