chore(package): update rollup-plugin-babel to version 4.0.3

Closes #18

Author: greenkeeper[bot]

package.json

@@ -75,7 +75,7 @@
     "regenerator-runtime": "^0.12.0",
     "rimraf": "^2.6.1",
     "rollup": "^0.64.1",
-    "rollup-plugin-babel": "^3.0.3",
+    "rollup-plugin-babel": "^4.0.3",
     "rollup-plugin-commonjs": "^9.1.0",
     "rollup-plugin-json": "^3.0.0",
     "rollup-plugin-node-resolve": "^3.3.0",