Merge pull request #35 from Halceyon/greenkeeper/rollup-2.0.0

Update rollup to the latest version 🚀

Author: Halceyon

package-lock.json

@@ -54,7 +54,7 @@
     "mocha": "^5.0.1",
     "mocha-lcov-reporter": "^1.3.0",
     "parse-json": "^5.0.0",
-    "rollup": "^1.12.0",
+    "rollup": "^2.0.0",
     "rollup-plugin-babel": "^4.3.3",
     "semantic-release": "^15.13.13",
     "sinon": "^6.0.0",