[neutron] 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: I7f542c2e898e9a828509cc8a801a96442ae93762

deliverables/stein/neutron-dynamic-routing.yaml

@@ -24,6 +24,10 @@ releases:
       - hash: c27bb1f190a60d201d616bebd42c60dae6afa545
         repo: openstack/neutron-dynamic-routing
     version: 14.0.0
+  - version: stein-em
+    projects:
+      - repo: openstack/neutron-dynamic-routing
+        hash: c27bb1f190a60d201d616bebd42c60dae6afa545
 branches:
   - location: 14.0.0.0rc1
     name: stable/stein