Use the new openstack-python3-jobs template

release repository did not change to use the latest template for unit
test jobs. This patch removes the versioned template and replaces it
with the unversioned one (that was introduced with patch [1]).

[1] https://review.opendev.org/856903

Change-Id: Ifcc10a162baeb8b9e5e7ea00199759b664bb0ce7

.zuul.yaml

@@ -2,7 +2,7 @@
     templates:
       - check-requirements
       - lib-forward-testing-python3
-      - openstack-python3-antelope-jobs
+      - openstack-python3-jobs
       - periodic-stable-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3