We need to upgrade prebundled React to v16.4.2 because React v16.4.1 has a vulnerability. Related to [React v16.4.2: Server-side vulnerability fix](https://reactjs.org/blog/2018/08/01/react-v-16-4-2.html), https://github.com/facebook/react/pull/13302 and https://github.com/facebook/react/pull/13303
We need to upgrade prebundled React to v16.4.2 because React v16.4.1 has a vulnerability.
Related to React v16.4.2: Server-side vulnerability fix, react/react#13302 and react/react#13303