Bump @nextcloud/auth from 1.1.0 to 1.2.1

Bumps [@nextcloud/auth](https://github.com/nextcloud/nextcloud-auth) from 1.1.0 to 1.2.1.
- [Release notes](https://github.com/nextcloud/nextcloud-auth/releases)
- [Changelog](https://github.com/nextcloud/nextcloud-auth/blob/master/CHANGELOG.md)
- [Commits](https://github.com/nextcloud/nextcloud-auth/compare/v1.1.0...v1.2.1

)

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