Update grunt-contrib-clean

Author: noahcooper

package.json

@@ -47,7 +47,7 @@
   },
   "devDependencies": {
     "grunt": "^1.0.3",
-    "grunt-contrib-clean": "^0.6.0",
+    "grunt-contrib-clean": "^2.0.0",
     "grunt-contrib-jshint": "^2.0.0",
     "grunt-contrib-nodeunit": "^2.0.0"
   },