chore(deps): update dependency rubocop to '~> 1.68.0'

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Diff for: Gemfile

@@ -6,7 +6,7 @@ gem 'chef', '~> 18.0'
 group :test do
   gem 'foodcritic', '~> 16.0'
   gem 'highline', '~> 2.1.0'
-  gem 'rubocop', '~> 1.67.0'
+  gem 'rubocop', '~> 1.68.0'
 end
 
 group :integration do