build(deps-dev): update minitest requirement from 5.25.5 to 5.26.0

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@v5.25.5...v5.26.0)

---
updated-dependencies:
- dependency-name: minitest
  dependency-version: 5.26.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

Gemfile

@@ -3,7 +3,7 @@ source "https://rubygems.org"
 gemspec
 
 group :test do
-  gem "minitest", "5.25.5"
+  gem "minitest", "5.26.0"
 
   gem "ruby_memcheck", "3.0.1" if Gem::Platform.local.os == "linux"