[kuryr-tempest-plugin] Tag xena-last

Xena branch is in Extended Maintenance 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 EM state then, Tempest and
its plugins compatible tag[2] needs to be released so that we can
keep testing the EM stable branches with that tag once master
Tempest and its plugins are not compatible[3].

Tagging 'xena-last' as well as a new version also with same hash.

[1] https://releases.openstack.org/wallaby/index.html
[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: I0e90376e2ac85884bd017e4ce93c3b37d7fc7d61

deliverables/bobcat/kuryr-tempest-plugin.yaml

@@ -8,3 +8,8 @@ repository-settings:
   openstack/kuryr-tempest-plugin: {}
 team: kuryr
 type: tempest-plugin
+releases:
+  - version: 0.15.0
+    projects:
+      - repo: openstack/kuryr-tempest-plugin
+        hash: 4af87c6e91c99ac97e4721d5be109fbfcf3f89a6

deliverables/xena/kuryr-tempest-plugin.yaml

@@ -17,3 +17,7 @@ releases:
     projects:
       - repo: openstack/kuryr-tempest-plugin
         hash: 19a3314ca8975ec737e104c2d2e4207fb9bf0fe0
+  - version: xena-last
+    projects:
+      - repo: openstack/kuryr-tempest-plugin
+        hash: 4af87c6e91c99ac97e4721d5be109fbfcf3f89a6