chore(package): update gulp-uglify to version 2.0.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -42,7 +42,7 @@
     "gulp-rename": "^1.2.0",
     "gulp-replace": "^0.5.0",
     "gulp-size": "^1.2.0",
-    "gulp-uglify": "^1.0.2",
+    "gulp-uglify": "^2.0.0",
     "gulp-util": "^3.0.0",
     "lazypipe": "^0.2.2",
     "mocha": "^3.0.0",