[zun-tempest-plugin] Tag zed-last

Zed branch is moving to unmaintained state now[1]. Tempest and tempest
plugins are branchless which means master version of Tempest and
its plugins is used to test the supported stable branches.

Once any stable branch is moved to unmaintained state then, Tempest and
its plugins compatible tag[2][3] needs to be released which can be used
to test the unmaintained stable branches.

Tagging 'zed-last' with latesh hash used in 4.9.0 version.

[1] https://review.opendev.org/q/topic:%22zed-unmaintained%22
[2] https://docs.openstack.org/tempest/latest/stable_branch_support_policy.html
[3] https://docs.openstack.org/tempest/latest/tempest_and_plugins_compatible_version_policy.html

Change-Id: I11ec1f5a9c2741de4ad9c2b0f06f033401149fb1

deliverables/zed/zun-tempest-plugin.yaml

@@ -14,3 +14,7 @@ releases:
     projects:
       - repo: openstack/zun-tempest-plugin
         hash: e8be4c7b08dd79da12d7c8962fb94c8f2ec4bc09
+  - version: zed-last
+    projects:
+      - repo: openstack/zun-tempest-plugin
+        hash: 8a0b3cf100c00c5ddbe13bc97b42f16a2bff95c1