Bump prettier from 2.1.2 to 2.2.1

Bumps [prettier](https://github.com/prettier/prettier) from 2.1.2 to 2.2.1.
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/master/CHANGELOG.md)
- [Commits](prettier/prettier@2.1.2...2.2.1)

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

Author: dependabot[bot]