define publish-openstack-docs-pti project template

As part of the python3-first goal, we need to update the PTI to
restore the ability to use tox to run the documentation build
commands. This will give us a way to configure each repo to have its
dependencies installed properly and to change the version of python
used in a self-testing patch to the tox.ini file.

Depends-On: https://review.openstack.org/580484
Change-Id: If87a3c80bed8dbbe9a93a6350056338e97d98162
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

zuul.d/jobs.yaml

@@ -547,6 +547,16 @@
     vars:
       tox_envlist: snap
 
+- job:
+    name: openstack-tox-docs
+    parent: openstack-tox
+    description: |
+      Run documentation build.
+
+      Uses tox with the ``docs`` environment.
+    vars:
+      tox_envlist: docs
+
 - job:
     name: openstack-tox-with-oslo-master-base
     parent: openstack-tox-py27

zuul.d/project-templates.yaml

@@ -85,6 +85,22 @@
       jobs:
         - publish-openstack-sphinx-docs-python3
 
+- project-template:
+    name: publish-openstack-docs-pti
+    description: |
+      Runs normal OpenStack PTI doc build and publication jobs
+      following the project testing interface.
+
+    check:
+      jobs:
+        - openstack-tox-docs
+    gate:
+      jobs:
+        - openstack-tox-docs
+    post:
+      jobs:
+        - publish-openstack-tox-docs
+
 - project-template:
     name: publish-openstack-sphinx-docs-infra
     description: |