chore: Update rubocop requirement from 1.81.1 to 1.81.6 (#1088)

Author: dependabot[bot]

Gemfile

@@ -22,5 +22,5 @@ gem 'minitest', '~> 5.0'
 gem 'minitest-reporters', '~> 1.1'
 gem 'pry'
 gem 'rake', '~> 13.0'
-gem 'rubocop', '1.81.1'
+gem 'rubocop', '1.81.6'
 gem 'yard', '~> 0.9.11'