[OpenStackAnsible] Transition Stein to EM

This transition the stein branch to extended maintenance.
Changes for bugfixes and things the team deems important are
still encouraged, but there will no longer be official releases
off of the branch.

Please +1 if the team is ready for us to proceed with this
transition, or -1 if there are any final backports currently in
flight that we should wait for. For the latter case, please
update the patch with the new commit hash after doing a final
release to get those changes out so we know to proceed with the
transition.

Change-Id: I6cbabdaf69016e562c04038ab843ceb14aad2690

deliverables/stein/openstack-ansible.yaml

@@ -108,6 +108,10 @@ releases:
     projects:
       - repo: openstack/openstack-ansible
         hash: f75f5dcd7fefc72b4485bcc634e9f4b14c39e978
+  - version: stein-em
+    projects:
+      - repo: openstack/openstack-ansible
+        hash: f75f5dcd7fefc72b4485bcc634e9f4b14c39e978
 cycle-highlights:
   - Tooling optimizations have been done that will result in faster
     and more reliable deployments.