build(deps-dev): bump prettier from 2.1.1 to 2.1.2

Bumps [prettier](https://github.com/prettier/prettier) from 2.1.1 to 2.1.2.
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/master/CHANGELOG.md)
- [Commits](prettier/prettier@2.1.1...2.1.2)

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