chore(package): update rollup to version 1.6.0

Closes #46

Author: greenkeeper[bot]

package.json

@@ -64,7 +64,7 @@
     "react-dom": "^16.3.2",
     "react-test-renderer": "^16.3.2",
     "regenerator-runtime": "^0.13.1",
-    "rollup": "^0.67.0",
+    "rollup": "^1.6.0",
     "rollup-plugin-babel": "^4.0.3",
     "rollup-plugin-commonjs": "^9.0.0",
     "rollup-plugin-json": "^3.0.0",