chore(package): update grunt-contrib-coffee to version 2.1.0

Closes #4

Author: greenkeeper[bot]

package.json

@@ -27,7 +27,7 @@
     "bower": "^1.3.12",
     "grunt": "^1.0.1",
     "grunt-bump": "0.8.0",
-    "grunt-contrib-coffee": "^1.0.0",
+    "grunt-contrib-coffee": "^2.1.0",
     "grunt-contrib-uglify": "^3.0.0"
   }
 }