[Security] Bump react-dom from 16.4.1 to 16.7.0

Bumps [react-dom](https://github.com/facebook/react) from 16.4.1 to 16.7.0. **This update includes security fixes.**
- [Release notes](https://github.com/facebook/react/releases)
- [Changelog](https://github.com/facebook/react/blob/master/CHANGELOG.md)
- [Commits](facebook/react@v16.4.1...v16.7.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support