Update rubocop requirement from ~> 0.67 to ~> 1.60

Updates the requirements on [rubocop](https://github.com/rubocop/rubocop) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop/releases)
- [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v0.67.0...v1.60.1)

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

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

signalwire.gemspec

@@ -31,7 +31,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'rake', '~> 13.0'
   spec.add_development_dependency 'rdoc', '~> 6.1'
   spec.add_development_dependency 'rspec', '~> 3.0'
-  spec.add_development_dependency 'rubocop', '~> 0.67'
+  spec.add_development_dependency 'rubocop', '~> 1.60'
   spec.add_development_dependency 'ruby-prof', '~> 0.17'
   spec.add_development_dependency 'simplecov', '~> 0.16'
   spec.add_development_dependency 'vcr', '~> 5.0'