[magnum-tempest-plugin] Tag train-last

Train 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 'train-last'[4] as well as a new version also with same hash.

[1] https://releases.openstack.org/train/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
[4] https://docs.openstack.org/project-team-guide/stable-branches.html#extended-maintenance

Change-Id: I9f10b574dba8dc33221c2aec1cd9451137b19250

deliverables/train/magnum-tempest-plugin.yaml

@@ -13,3 +13,7 @@ releases:
     projects:
       - repo: openstack/magnum-tempest-plugin
         hash: 85700fc464f8fad9cb323659278cdee101d8aaed
+  - version: train-last
+    projects:
+      - repo: openstack/magnum-tempest-plugin
+        hash: 7762c6e80102a27cfd01a22242c81533e3d04366

deliverables/xena/magnum-tempest-plugin.yaml

@@ -9,3 +9,8 @@ repository-settings:
     tarball-base: magnum_tempest_plugin
 team: magnum
 type: tempest-plugin
+releases:
+  - version: 1.4.0
+    projects:
+      - repo: openstack/magnum-tempest-plugin
+        hash: 7762c6e80102a27cfd01a22242c81533e3d04366