build(deps): update cucumber-messages requirement from ~> 19.1, >= 19…

….1.4 to >= 19.1.4, < 22.0

Updates the requirements on [cucumber-messages](https://github.com/cucumber/messages) to permit the latest version.
- [Release notes](https://github.com/cucumber/messages/releases)
- [Changelog](https://github.com/cucumber/messages/blob/main/CHANGELOG.md)
- [Commits](cucumber/messages@v19.1.4...v21.0.1)

---
updated-dependencies:
- dependency-name: cucumber-messages
  dependency-type: direct:production
...

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

ruby/cucumber-gherkin.gemspec

@@ -20,7 +20,7 @@ Gem::Specification.new do |s|
     'source_code_uri' => 'https://github.com/cucumber/gherkin/blob/main/ruby'
   }
 
-  s.add_dependency 'cucumber-messages', '~> 19.1', '>= 19.1.4'
+  s.add_dependency 'cucumber-messages', '>= 19.1.4', '< 22.0'
 
   s.add_development_dependency 'rake', '~> 13.0', '>= 13.0.6'
   s.add_development_dependency 'rspec', '~> 3.11', '>= 3.11.0'