Remove stable/2023.1 job from master gate

stable/2023.1 is planned to be in unmaintained state[1]
and with python 3.8 drop from Tempest[2], we have to pin the
Tempest for stable/2023.1 testing[3]. This means Tempest and
its plugin master does not need to support stable/2023.1.

With that we can remove the stable/2023.1 jobs from tempest
plugin master jobs.

[1] https://lists.openstack.org/archives/list/openstack-discuss@>
[2] https://review.opendev.org/c/openstack/tempest/+/933398
[3] https://review.opendev.org/c/openstack/devstack/+/933704

Change-Id: I4721511d77c319ab4848941be8eb6d8541fe2835
1 file changed