Switch to 2023.1 Python3 unit tests and generic template name

This is an automatically generated patch to ensure unit testing
is in place for all the of the tested runtimes for antelope. Also,
updating the template name to generic one.

See also the PTI in governance [1].

[1]: https://governance.openstack.org/tc/reference/project-testing-interface.html

Change-Id: Ibfe85c550cf20a7b5f4570700df348bb41ed261a