[solum-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: I78f69661eff440c23b08ef44dabffc502916007c

deliverables/antelope/solum-tempest-plugin.yaml

@@ -8,3 +8,8 @@ repository-settings:
   openstack/solum-tempest-plugin: {}
 team: solum
 type: tempest-plugin
+releases:
+  - version: 2.6.0
+    projects:
+      - repo: openstack/solum-tempest-plugin
+        hash: ca9c30e4dd0de9997468ef2714ba92eea276cdc3

deliverables/wallaby/solum-tempest-plugin.yaml

@@ -13,3 +13,7 @@ releases:
     projects:
       - repo: openstack/solum-tempest-plugin
         hash: 80e23bb97926308505bc0ac206974468b38efe4e
+  - version: wallaby-last
+    projects:
+      - repo: openstack/solum-tempest-plugin
+        hash: ca9c30e4dd0de9997468ef2714ba92eea276cdc3