[storlets] Transition Rocky to EM

This transition the rocky 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: I8128b420bd97ef92acb6b74e55fcf54651974ebb

deliverables/rocky/storlets.yaml

@@ -25,6 +25,10 @@ releases:
       - repo: openstack/storlets
         hash: 201f2b99411ee78af1882fc550166aa58d4b1d8a
     version: 2.0.0
+  - version: rocky-em
+    projects:
+      - repo: openstack/storlets
+        hash: 201f2b99411ee78af1882fc550166aa58d4b1d8a
 branches:
   - location: 2.0.0.0rc1
     name: stable/rocky