Switch to 2023.1 Python3 unit tests and generic template name

This is a 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: Ib9588e4421bc6748b1f63ba58c0594c90184005e

zuul.d/project.yaml

@@ -1,3 +1,3 @@
 - project:
     templates:
-      - openstack-python3-zed-jobs
+      - openstack-python3-jobs