chore(package): update grunt-contrib-uglify to version 2.0.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -33,7 +33,7 @@
     "grunt-contrib-jshint": "1.0.0",
     "grunt-contrib-less": "1.2.0",
     "grunt-contrib-qunit": "0.5.2",
-    "grunt-contrib-uglify": "1.0.1",
+    "grunt-contrib-uglify": "2.0.0",
     "grunt-contrib-watch": "1.0.0",
     "grunt-html": "5.0.1",
     "grunt-jsbeautifier": "0.2.10",