[Tempest Plugins] Tag stein-last

Stein branch is in Extended Maintenance now[1]. All Tempest
plugins are branchless which means master version of Tempest
and its plugins is used to test the supported stable branches.

Once stable branch is moved to EM state then, Tempest and its
plugins compatible tag needs to be released so that we can
keep testing the EM stable branches with this tag once master
Tempest and its plugins are not compatible[2].

This tag will help for testing the stable/stein with single
compatible tag of Tempest and its plugins.

Tagging 'stein-last' as well as a new version also with same hash.
Documenting this new tag name here
- https://review.opendev.org/c/openstack/project-team-guide/+/769821

More detail on compatible version policy for Tempest and its
plugins is here
- https://docs.openstack.org/tempest/latest/tempest_and_plugins_compatible_version_policy.html

[1] https://releases.openstack.org/stein/index.html
[2] https://docs.openstack.org/tempest/latest/stable_branch_support_policy.html

Change-Id: I19cf2b717ad97c7219d5c12ac09550279ee9b4bf

deliverables/stein/barbican-tempest-plugin.yaml

@@ -13,3 +13,7 @@ releases:
       - hash: 123dd7d4162c39a1cb4b4c1b09a5dceaee127eb6
         repo: openstack/barbican-tempest-plugin
     version: 0.2.0
+  - version: stein-last
+    projects:
+      - repo: openstack/barbican-tempest-plugin
+        hash: 53dcab70f26f8e990fce425ee1005ef3f775d174

deliverables/wallaby/barbican-tempest-plugin.yaml

@@ -9,3 +9,8 @@ repository-settings:
     tarball-base: barbican_tempest_plugin
 team: barbican
 type: tempest-plugin
+releases:
+  - version: 1.2.0
+    projects:
+      - repo: openstack/barbican-tempest-plugin
+        hash: 53dcab70f26f8e990fce425ee1005ef3f775d174