chore(package): update rollup to version 2.3.1

Closes #245

Author: greenkeeper[bot]

package.json

@@ -67,7 +67,7 @@
         "platform": "^1.3.5",
         "prettier": "^1.18.2",
         "rimraf": "^2.6.3",
-        "rollup": "^1.17.0",
+        "rollup": "^2.3.1",
         "rollup-plugin-alias": "^1.5.2",
         "rollup-plugin-babel": "^4.3.3",
         "rollup-plugin-commonjs": "^10.0.1",