bump versions for release 1.2.0

Author: amirkaws

version.json

@@ -2,7 +2,7 @@
   "Core": {
     "Common": "1.1.0",
     "Logging": "1.1.0",
-    "Metrics": "1.1.0",
+    "Metrics": "1.2.0",
     "Tracing": "1.1.0"
   }
 }