chore(package): update ws to version 6.0.0 (#269)

Author: greenkeeper[bot]

package.json

@@ -81,6 +81,6 @@
     "uglifyjs-webpack-plugin": "^1.2.7",
     "webpack": "^4.16.1",
     "webpack-merge": "^4.1.3",
-    "ws": "^5.2.2"
+    "ws": "^6.0.0"
   }
 }