Update rubocop requirement from 1.43.0 to 1.44.1 (#194)

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@v1.43.0...v1.44.1)

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

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

Gemfile

@@ -6,7 +6,7 @@ gem "minitest-ci", "~> 3.4"
 gem "minitest-reporters", "~> 1.1"
 gem "mocha", "~> 2.0"
 gem "rake", "~> 13.0"
-gem "rubocop", "1.43.0"
+gem "rubocop", "1.44.1"
 gem "rubocop-minitest", "0.26.0"
 gem "rubocop-packaging", "0.5.2"
 gem "rubocop-performance", "1.15.2"