[placement] 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: Ibc49f7d032c1f8922a181cbcd3954b9dccf622eb

deliverables/stein/os-resource-classes.yaml

@@ -19,6 +19,10 @@ releases:
       - hash: 2d4672e5f342a4a5aec4ceca885cd7d966134ebb
         repo: openstack/os-resource-classes
     version: 0.3.0
+  - version: stein-em
+    projects:
+      - repo: openstack/os-resource-classes
+        hash: 2d4672e5f342a4a5aec4ceca885cd7d966134ebb
 branches:
   - location: 0.3.0
     name: stable/stein

deliverables/stein/placement.yaml

@@ -34,6 +34,10 @@ releases:
         repo: openstack/placement
         tarball-base: openstack-placement
     version: 1.1.0
+  - version: stein-em
+    projects:
+      - repo: openstack/placement
+        hash: bdcbb2604bcbb195fa6e3a1b504ec2c31531308b
 branches:
   - location: 1.0.0.0rc1
     name: stable/stein