chore(package): update rollup to version 0.47.2

Closes #12

Author: greenkeeper[bot]

package.json

@@ -46,7 +46,7 @@
     "eslint-config-ngryman": "^1.4.0",
     "nyc": "^10.0.0",
     "pre-commit": "^1.1.3",
-    "rollup": "^0.41.0",
+    "rollup": "^0.47.2",
     "spy": "^1.0.0"
   },
   "ava": {