build(deps-dev): update minitest requirement from 5.21.2 to 5.22.2

Updates the requirements on [minitest](https://github.com/minitest/minitest) to permit the latest version.
- [Changelog](https://github.com/minitest/minitest/blob/master/History.rdoc)
- [Commits](minitest/minitest@v5.21.2...v5.22.2)

---
updated-dependencies:
- dependency-name: minitest
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile

@@ -3,7 +3,7 @@ source "https://rubygems.org"
 gemspec
 
 group :development do
-  gem "minitest", "5.21.2"
+  gem "minitest", "5.22.2"
 
   gem "rake-compiler", "1.2.7"
   gem "rake-compiler-dock", "1.4.0"