Update rubocop requirement from = 1.41.1 to = 1.42.0 (#16)

Author: dependabot[bot]

fastlane-plugin-mint.gemspec

@@ -23,7 +23,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency('rake')
   spec.add_development_dependency('rspec')
   spec.add_development_dependency('rspec_junit_formatter')
-  spec.add_development_dependency('rubocop', '1.41.1')
+  spec.add_development_dependency('rubocop', '1.42.0')
   spec.add_development_dependency('rubocop-performance')
   spec.add_development_dependency('rubocop-require_tools')
   spec.add_development_dependency('simplecov')