Update rubocop requirement from ~> 1.80.2 to ~> 1.81.1

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@v1.80.2...v1.81.1)

---
updated-dependencies:
- dependency-name: rubocop
  dependency-version: 1.81.1
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Gemfile

@@ -13,7 +13,7 @@ end
 
 group :development, :test do
   gem 'rake'
-  gem 'rubocop', '~> 1.80.2', require: false
+  gem 'rubocop', '~> 1.81.1', require: false
   gem 'rubocop-minitest', require: false
   gem 'rubocop-rake', require: false
   gem 'simplecov', require: false