[zun] Transition Stein to End of Life

As announced on mailing list [1], this patch transitions the Stein
branch to End of Life. The last patch of the branch will be tagged with
stein-eol tag. stable/stein branch cannot be used anymore and will be
deleted if this patch merges.

This is needed as stable/stein is not actively maintained in recent
period, thus gates are mostly broken due to job failures. Besides,
by removing these branches, infra resources will be freed up, too.

Please try to identify any zuul job, that is defined outside of the
repositories in this patch (for example in openstack-zuul-jobs, etc.)
and won't be used anymore if stable/stein is deleted. Propose a job
removal patch for them.

Please +1 if the team is ready for us to proceed with this transition,
or -1 if there are still some activity on the branch and the team wants
to continue to maintain it.

[1] https://lists.openstack.org/pipermail/openstack-discuss/2023-September/034965.html

Change-Id: I61720b04e9ed54eaf503cfcfef092062fb378b18

deliverables/stein/python-zunclient.yaml

@@ -33,6 +33,10 @@ releases:
     projects:
       - repo: openstack/python-zunclient
         hash: 75517b5284c99e3d2be051963a42f981f3959f63
+  - version: stein-eol
+    projects:
+      - repo: openstack/python-zunclient
+        hash: 75517b5284c99e3d2be051963a42f981f3959f63
 repository-settings:
   openstack/python-zunclient: {}
 branches:

deliverables/stein/zun-ui.yaml

@@ -16,6 +16,10 @@ releases:
     projects:
       - repo: openstack/zun-ui
         hash: 58ca0552d1e9bfad966431abb6292f57e67a6180
+  - version: stein-eol
+    projects:
+      - repo: openstack/zun-ui
+        hash: 58ca0552d1e9bfad966431abb6292f57e67a6180
 repository-settings:
   openstack/zun-ui: {}
 branches:

deliverables/stein/zun.yaml

@@ -27,6 +27,10 @@ releases:
     projects:
       - repo: openstack/zun
         hash: 307617805dfb2ca32761c2db3aaa472b6811a7bf
+  - version: stein-eol
+    projects:
+      - repo: openstack/zun
+        hash: a1c2fdeb60ad750f7ab3f3d74bd023152bcbe1fb
 branches:
   - location: 3.0.0.0rc1
     name: stable/stein