Update rubocop-govuk requirement from = 4.16.0 to = 4.16.1

Updates the requirements on [rubocop-govuk](https://github.com/alphagov/rubocop-govuk) to permit the latest version.
- [Changelog](https://github.com/alphagov/rubocop-govuk/blob/main/CHANGELOG.md)
- [Commits](alphagov/rubocop-govuk@v4.16.0...v4.16.1)

---
updated-dependencies:
- dependency-name: rubocop-govuk
  dependency-type: direct:development
...

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

slimmer.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency "rack-test", "~> 2"
   s.add_development_dependency "rails", "~> 7"
   s.add_development_dependency "rake"
-  s.add_development_dependency "rubocop-govuk", "4.16.0"
+  s.add_development_dependency "rubocop-govuk", "4.16.1"
   s.add_development_dependency "webmock", "~> 3.8"
 
   s.files = Dir[