Update extension bundle ID in host.json (#23)

Author: manvkaur

src/host.json

@@ -9,7 +9,7 @@
     }
   },
   "extensionBundle": {
-    "id": "Microsoft.Azure.Functions.ExtensionBundle.Experimental",
+    "id": "Microsoft.Azure.Functions.ExtensionBundle",
     "version": "[4.*, 5.0.0)"
   }
-}
+}