Update voxpupuli-rubocop requirement from ~> 4.2.0 to ~> 5.1.0

Updates the requirements on [voxpupuli-rubocop](https://github.com/voxpupuli/voxpupuli-rubocop) to permit the latest version.
- [Release notes](https://github.com/voxpupuli/voxpupuli-rubocop/releases)
- [Changelog](https://github.com/voxpupuli/voxpupuli-rubocop/blob/master/CHANGELOG.md)
- [Commits](voxpupuli/voxpupuli-rubocop@v4.2.0...v5.1.0)

---
updated-dependencies:
- dependency-name: voxpupuli-rubocop
  dependency-version: 5.1.0
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

packaging.gemspec

@@ -15,7 +15,7 @@ Gem::Specification.new do |gem|
   gem.required_ruby_version = '>= 3.2.0'
 
   gem.add_development_dependency('rspec', ['>= 2.14.1', '< 4'])
-  gem.add_development_dependency('voxpupuli-rubocop', '~> 4.2.0')
+  gem.add_development_dependency('voxpupuli-rubocop', '~> 5.1.0')
   gem.add_dependency('artifactory', ['~> 3'])
   gem.add_dependency('base64', ['< 0.4'])
   gem.add_dependency('benchmark', '< 0.6')