chore(package): update gulp-uglify to version 2.1.0 (#1704)

https://greenkeeper.io/

package.json

@@ -48,7 +48,7 @@
     "gulp-sass-lint": "~1.3.1",
     "gulp-size": "~2.1.0",
     "gulp-sourcemaps": "~2.4.0",
-    "gulp-uglify": "~2.0.0",
+    "gulp-uglify": "~2.1.0",
     "gulp-useref": "~3.1.0",
     "gulp-util": "~3.0.7",
     "gulp-watch": "~4.3.8",