[ironic-tempest-plugin] Tag wallaby-last

Wallaby 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 'wallaby-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: Ibe6993d95592fde1668569f32c19005bde990f71

deliverables/antelope/ironic-tempest-plugin.yaml

@@ -8,3 +8,8 @@ repository-settings:
   openstack/ironic-tempest-plugin: {}
 team: ironic
 type: tempest-plugin
+releases:
+  - version: 2.6.0
+    projects:
+      - repo: openstack/ironic-tempest-plugin
+        hash: 4684f915b58d2c161295100802dec7076920451f

deliverables/wallaby/ironic-tempest-plugin.yaml

@@ -13,3 +13,7 @@ releases:
     projects:
       - repo: openstack/ironic-tempest-plugin
         hash: 5aa5765508fa0b282d60c1ecafddc35f73a046c1
+  - version: wallaby-last
+    projects:
+      - repo: openstack/ironic-tempest-plugin
+        hash: 4684f915b58d2c161295100802dec7076920451f