Update rubocop-rails requirement from = 2.17.2 to = 2.17.3

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@v2.17.2...v2.17.3)

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

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

rubocop-govuk.gemspec

@@ -17,7 +17,7 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "rubocop", "1.39.0"
   spec.add_dependency "rubocop-ast", "1.23.0"
-  spec.add_dependency "rubocop-rails", "2.17.2"
+  spec.add_dependency "rubocop-rails", "2.17.3"
   spec.add_dependency "rubocop-rake", "0.6.0"
   spec.add_dependency "rubocop-rspec", "2.15.0"
 end