Switch to Xenial: project-team-guide-publish
Switch to Xenial: project-team-guide-publish

The docs jobs run already on xenial, change the publish job directly
from trusty to xenial since the repo has only a master branch.

Change-Id: Ifc8ba3e934e5d0e94fc9efd73b2e068f70fa180b

openstack-infra/project-config,openstack-infra/project-config,Tesora/tesora-project-config,Tesora/tesora-project-config