[octavia-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: I643ecc29633d4b0265b18584f69faf53c3b18bb1

deliverables/bobcat/octavia-tempest-plugin.yaml

@@ -8,3 +8,8 @@ repository-settings:
 storyboard: 908
 team: octavia
 type: tempest-plugin
+releases:
+  - version: 2.4.0
+    projects:
+      - repo: openstack/octavia-tempest-plugin
+        hash: b9af9163cb7a5277e4c72dc1becb563148f7fa1b

deliverables/xena/octavia-tempest-plugin.yaml

@@ -16,4 +16,8 @@ releases:
     projects:
       - repo: openstack/octavia-tempest-plugin
         hash: 605899c1a92756b568ed14478158ddafbcff3d18
+  - version: xena-last
+    projects:
+      - repo: openstack/octavia-tempest-plugin
+        hash: b9af9163cb7a5277e4c72dc1becb563148f7fa1b
 type: tempest-plugin