chore(package): update grunt-contrib-internal to version 3.1.0

Closes #24

Author: greenkeeper[bot]

package.json

@@ -26,7 +26,7 @@
     "grunt": "^1.0.1",
     "grunt-contrib-clean": "^1.0.0",
     "grunt-contrib-concat": "^1.0.0",
-    "grunt-contrib-internal": "^1.1.0",
+    "grunt-contrib-internal": "^3.1.0",
     "grunt-contrib-jshint": "^1.0.0",
     "grunt-contrib-nodeunit": "^1.0.0"
   },