chore(package): update rollup-plugin-babel to version 4.0.2

Closes #5

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "eslint": "^5.0.1",
     "jest": "^23.2.0",
     "rollup": "^0.62.0",
-    "rollup-plugin-babel": "^3.0.4",
+    "rollup-plugin-babel": "^4.0.2",
     "rollup-plugin-commonjs": "^9.1.3",
     "rollup-plugin-node-resolve": "^3.3.0"
   },