all: update @google-cloud/common dependency

Author: stephenplusplus

package.json

@@ -50,7 +50,7 @@
     "datastore"
   ],
   "dependencies": {
-    "@google-cloud/common": "^0.5.0",
+    "@google-cloud/common": "^0.6.0",
     "arrify": "^1.0.0",
     "concat-stream": "^1.5.0",
     "create-error-class": "^3.0.2",