[cinder] Release cinderlib for 2023.1 Antelope and cut branch

Release cinderlib 6.0.0 as the 2023.1 Antelope cycle-trailing release
and cut the stable/2023.1 branch.

Change-Id: Idb373f36f60d8ad8f668f9f587fc1b962493ab0c

deliverables/antelope/cinderlib.yaml

@@ -5,3 +5,11 @@ team: cinder
 type: trailing
 repository-settings:
   openstack/cinderlib: {}
+releases:
+  - version: 5.1.0
+    projects:
+      - repo: openstack/cinderlib
+        hash: 18c81f0023ff378427dff49b188a14b999c341cf
+branches:
+  - name: stable/2023.1
+    location: 5.1.0