Update rubocop-rails requirement from ~> 2.29.1 to ~> 2.31.0 (#193)

Updates the requirements on [rubocop-rails](https://github.com/rubocop/rubocop-rails) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rails@v2.29.1...v2.31.0)

---
updated-dependencies:
- dependency-name: rubocop-rails
  dependency-version: 2.31.0
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: jonathan schatz <[email protected]>

Author: dependabot[bot]

cloudflare-rails.gemspec

@@ -26,7 +26,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'rspec-rails', '~> 7.1.1'
   spec.add_development_dependency 'rubocop', '~> 1.75.2'
   spec.add_development_dependency 'rubocop-performance', '~> 1.23.1'
-  spec.add_development_dependency 'rubocop-rails', '~> 2.29.1'
+  spec.add_development_dependency 'rubocop-rails', '~> 2.31.0'
   spec.add_development_dependency 'rubocop-rspec', '~> 3.6.0'
   spec.add_development_dependency 'webmock', '~> 3.25.0'
   spec.add_dependency 'actionpack', '>= 7.1.0', '< 8.1.0'