chore(deps): update rubocop requirement from 1.81.1 to 1.81.6 (#639)

Author: dependabot[bot]

Gemfile

@@ -8,7 +8,7 @@ gem 'minitest', '~> 5.0'
 gem 'minitest-reporters', '~> 1.1'
 gem 'parallel_tests'
 gem 'rake', '~> 13.0'
-gem 'rubocop', '1.81.1'
+gem 'rubocop', '1.81.6'
 gem 'simplecov'
 gem 'steep', '~> 1.9.3'
 gem 'webmock', '~> 3.25.0'