[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: Id4c39b10e7e6685958a490ece8c37ad66d9769ba

deliverables/stein/monasca-tempest-plugin.yaml

@@ -16,3 +16,7 @@ releases:
       - hash: 71817e2ede8365306a5393fe3aee050ec9db4092
         repo: openstack/monasca-tempest-plugin
     version: 1.0.0
+  - version: stein-last
+    projects:
+      - repo: openstack/monasca-tempest-plugin
+        hash: a46fb592455293cac03e713b7870e6bbeb399e0c

deliverables/wallaby/monasca-tempest-plugin.yaml

@@ -8,3 +8,8 @@ repository-settings:
   openstack/monasca-tempest-plugin: {}
 team: monasca
 type: tempest-plugin
+releases:
+  - version: 2.2.0
+    projects:
+      - repo: openstack/monasca-tempest-plugin
+        hash: a46fb592455293cac03e713b7870e6bbeb399e0c