Update rubocop-rspec requirement from = 2.29.2 to = 2.30.0

Updates the requirements on [rubocop-rspec](https://github.com/rubocop/rubocop-rspec) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop-rspec/releases)
- [Changelog](https://github.com/rubocop/rubocop-rspec/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rspec@v2.29.2...v2.30.0)

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

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

Author: dependabot[bot]

rubocop-govuk.gemspec

@@ -19,5 +19,5 @@ Gem::Specification.new do |spec|
   spec.add_dependency "rubocop-ast", "1.31.3"
   spec.add_dependency "rubocop-rails", "2.25.0"
   spec.add_dependency "rubocop-rake", "0.6.0"
-  spec.add_dependency "rubocop-rspec", "2.29.2"
+  spec.add_dependency "rubocop-rspec", "2.30.0"
 end