Update rubocop requirement from ~> 1.82.0 to ~> 1.84.0

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@v1.82.0...v1.84.0)

---
updated-dependencies:
- dependency-name: rubocop
  dependency-version: 1.84.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

Gemfile

@@ -5,5 +5,5 @@ gemspec
 group :development, :test do
   gem 'rake', '~> 13.3.1'
   gem 'pry-byebug'
-  gem 'rubocop', '~> 1.82.0'
+  gem 'rubocop', '~> 1.84.0'
 end