Update rspec-rails requirement from ~> 5.0 to ~> 6.0
Update rspec-rails requirement from ~> 5.0 to ~> 6.0

Updates the requirements on [rspec-rails](https://github.com/rspec/rspec-rails) to permit the latest version.
- [Release notes](https://github.com/rspec/rspec-rails/releases)
- [Changelog](https://github.com/rspec/rspec-rails/blob/main/Changelog.md)
- [Commits](https://github.com/rspec/rspec-rails/compare/v5.0.0...v6.0.0)

---
updated-dependencies:
- dependency-name: rspec-rails
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
doorkeeper-gem/doorkeeper,doorkeeper-gem/doorkeeper,doorkeeper-gem/doorkeeper