Update sensiolabs/security-checker requirement from ^5.0 to ^6.0
Update sensiolabs/security-checker requirement from ^5.0 to ^6.0

Updates the requirements on [sensiolabs/security-checker](https://github.com/sensiolabs/security-checker) to permit the latest version.
- [Release notes](https://github.com/sensiolabs/security-checker/releases)
- [Commits](https://github.com/sensiolabs/security-checker/compare/v5.0.0...v6.0.0)
alister/ReservedNamesBundle,alister/ReservedNamesBundle