Bumps [rack](https://github.com/rack/rack) from 1.6.11 to 1.6.12. **This update includes a security fix.** - [Release notes](https://github.com/rack/rack/releases) - [Changelog](https://github.com/rack/rack/blob/master/CHANGELOG.md) - [Commits](https://github.com/rack/rack/compare/1.6.11...1.6.12) Signed-off-by: dependabot-preview[bot] <support@dependabot.com>