[murano] Create 2023.1 branch for client and non-client libs

This creates the stable/2023.1 branch for all client and non-client
libraries now that we are past the library freeze.

If the team wants to wait for a specific patch to make it to the
library (for example if the gate of the deliverable is broken and
needs to be fixed before branching), then someone from the team can
-1 the patch to have it held, or update that patch with a different
commit SHA.

Note that we are already late with this patch as the deadline was
this week. Please respond as soon as possible, because early next
week we need to merge the patch.

Change-Id: I78f119233461a3381d511d84ee5f1db85811ce05

deliverables/antelope/python-muranoclient.yaml

@@ -11,3 +11,6 @@ releases:
     projects:
       - repo: openstack/python-muranoclient
         hash: 862c7bee70b42db0bc0bf089ce8e611c15851e7f
+branches:
+  - name: stable/2023.1
+    location: 2.6.0