Update rubocop requirement from 1.82.1 to 1.84.0 (#216)

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@v1.82.1...v1.84.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Gemfile

@@ -7,7 +7,7 @@ gem "irb"
 gem "minitest", "~> 6.0"
 gem "minitest-rg", "~> 5.3"
 gem "rake", "~> 13.0"
-gem "rubocop", "1.82.1"
+gem "rubocop", "1.84.0"
 gem "rubocop-minitest", "0.38.2"
 gem "rubocop-packaging", "0.6.0"
 gem "rubocop-performance", "1.26.1"