Update rollup to the latest version 🚀 (#306)

## The devDependency [rollup](https://github.com/rollup/rollup) was updated from `0.68.2` to `1.0.0`.
This version is **not covered** by your **current version range**.

If you don’t accept this pull request, your project will work just like it did before. However, you might be missing out on a bunch of new features, fixes and/or performance improvements from the dependency update.

---

[Find out more about this release](https://github.com/rollup/rollup).

<details>
  <summary>FAQ and help</summary>

  There is a collection of [frequently asked questions](https://greenkeeper.io/faq.html). If those don’t help, you can always [ask the humans behind Greenkeeper](https://github.com/greenkeeperio/greenkeeper/issues/new).
</details>

---


Your [Greenkeeper](https://greenkeeper.io) bot 🌴

package.json

@@ -44,7 +44,7 @@
     "eslint-plugin-import": "^2.14.0",
     "is-builtin-module": "^3.0.0",
     "mocha": "^5.0.1",
-    "rollup": "^0.68.0",
+    "rollup": "^1.0.0",
     "rollup-plugin-babel": "^4.0.2",
     "rollup-plugin-node-resolve": "^4.0.0",
     "sinon": "^7.0.0",