[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: Id0e5386655b29d7c42930957db1b1bc0103865dd

deliverables/stein/neutron-tempest-plugin.yaml

@@ -13,3 +13,7 @@ releases:
       - hash: e40f6012424ff0c414dfd20d923c0ab7c8251af3
         repo: openstack/neutron-tempest-plugin
     version: 0.3.0
+  - version: stein-last
+    projects:
+      - repo: openstack/neutron-tempest-plugin
+        hash: fd8bf4d3b08efd4c83151a8d59329615bff1cca2

deliverables/wallaby/neutron-tempest-plugin.yaml

@@ -9,3 +9,8 @@ repository-settings:
     tarball-base: neutron-tempest-plugin
 team: neutron
 type: tempest-plugin
+releases:
+  - version: 1.3.0
+    projects:
+      - repo: openstack/neutron-tempest-plugin
+        hash: fd8bf4d3b08efd4c83151a8d59329615bff1cca2