build(deps-dev): update voxpupuli-rubocop requirement from ~> 2.6.0 t…

…o ~> 2.7.0

Updates the requirements on [voxpupuli-rubocop](https://github.com/voxpupuli/voxpupuli-rubocop) to permit the latest version.
- [Changelog](https://github.com/voxpupuli/voxpupuli-rubocop/blob/master/CHANGELOG.md)
- [Commits](voxpupuli/voxpupuli-rubocop@v2.6.0...v2.7.0)

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

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

beaker.gemspec

@@ -22,7 +22,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'fakefs', '~> 2.4'
   s.add_development_dependency 'rake', '~> 13.0'
   s.add_development_dependency 'rspec', '~> 3.0'
-  s.add_development_dependency 'voxpupuli-rubocop', '~> 2.6.0'
+  s.add_development_dependency 'voxpupuli-rubocop', '~> 2.7.0'
 
   # Run time dependencies
   s.add_runtime_dependency 'minitar', '~> 0.6'