[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: Ifaba5f4e460c2a8ee8d00d430678f82dbfb6b321

deliverables/stein/freezer-tempest-plugin.yaml

@@ -13,3 +13,7 @@ releases:
       - hash: 0f2b0e9a8424e50adca10fdfa64359f6df93c569
         repo: openstack/freezer-tempest-plugin
     version: 0.1.0
+  - version: stein-last
+    projects:
+      - repo: openstack/freezer-tempest-plugin
+        hash: 564b03758e0dcae8d41a1a3cc957efe0bce0e750

deliverables/wallaby/freezer-tempest-plugin.yaml

@@ -9,3 +9,8 @@ repository-settings:
     tarball-base: freezer_tempest_plugin
 team: freezer
 type: tempest-plugin
+releases:
+  - version: 1.2.0
+    projects:
+      - repo: openstack/freezer-tempest-plugin
+        hash: 564b03758e0dcae8d41a1a3cc957efe0bce0e750