Change storlets release model to cycle-with-milestones

And, add the first rocky milestone commit hash.

Change-Id: I08015ec6c5e0a0f3cd552c2b5a077c0fb86df148

deliverables/rocky/storlets.yaml

@@ -2,6 +2,11 @@
 launchpad: storlets
 team: storlets
 type: service
-release-model: cycle-with-intermediary
+release-model: cycle-with-milestones
+releases:
+  - version: 2.0.0.0b1
+    projects:
+      - repo: openstack/storlets
+        hash: a8b61f9961417ab4e8386550afd9fed836b1c376
 repository-settings:
   openstack/storlets: {}