fix(package): update ws to version 2.1.0 (#268)

https://greenkeeper.io/

package.json

@@ -115,7 +115,7 @@
     "retry-promise": "1.0.0",
     "socket.io": "1.7.3",
     "selenium-webdriver": "3.1.0",
-    "ws": "2.0.3"
+    "ws": "2.1.0"
   },
   "devDependencies": {
     "@types/body-parser": "0.0.34",