Prepare for official Queens release

Prepare the metadata for the official Queens release.

Change-Id: I3663c154d3d1561884aeb14ac37f0c587436f884

metadata.json

@@ -11,7 +11,7 @@
         },
         {
             "name": "openstack/openstacklib",
-            "version_requirement": ">=12.2.0 <13.0.0"
+            "version_requirement": ">=12.3.0 <13.0.0"
         }
     ],
     "description": "Installs and configures OpenStack Oslo.",
@@ -57,5 +57,5 @@
     ],
     "source": "git://github.com/openstack/puppet-oslo.git",
     "summary": "Puppet module for OpenStack Oslo",
-    "version": "12.2.0"
+    "version": "12.3.0"
 }