Update rails requirement from >= 4.2, < 6 to >= 4.2, < 7
Update rails requirement from >= 4.2, < 6 to >= 4.2, < 7

Updates the requirements on [rails](https://github.com/rails/rails) to permit the latest version.
- [Release notes](https://github.com/rails/rails/releases)
- [Commits](https://github.com/rails/rails/compare/v4.2.0...v5.2.3)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
zooppa/administrate-field-carrierwave,zooppa/administrate-field-carrierwave