685f9cdd92
As of https://github.com/ansible/ansible/commit/724800c (and now 2.12.0b1), ansible started requiring Python 3.8 or later on controllers. Switch our representative bridge.openstack.org test nodes to the ubuntu-focal label which has 3.8.10 as its default python3 so we can determine whether it's safe to upgrade production similarly. Change-Id: Ie1dc4dfaaf08ab74bf59717610231855926e9d19