chore(package): update rollup-plugin-babel to version 4.0.1

Closes #69

Author: greenkeeper[bot]

package.json

@@ -81,7 +81,7 @@
     "phantomjs-prebuilt": "2.1.14",
     "rimraf": "2.5.4",
     "rollup": "0.38.1",
-    "rollup-plugin-babel": "2.7.1",
+    "rollup-plugin-babel": "4.0.1",
     "sinon": "1.17.7",
     "sinon-chai": "2.8.0",
     "webpack": "1.14.0"