monitoring: update gapic layer

Author: stephenplusplus

packages/monitoring/package.json

@@ -52,7 +52,7 @@
     "stackdriver"
   ],
   "dependencies": {
-    "google-gax": "^0.7.0",
+    "google-gax": "^0.8.1",
     "google-proto-files": "^0.8.3",
     "extend": "^3.0.0"
   },