chore(deps-dev): update minitest requirement from ~> 5.0 to ~> 6.0

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@v5.0.0...v6.0.3)

---
updated-dependencies:
- dependency-name: minitest
  dependency-version: 6.0.3
  dependency-type: direct:development
...

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

Author: dependabot[bot]

api/opentelemetry-api.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency 'benchmark-ipsa', '~> 0.2.0'
   spec.add_development_dependency 'concurrent-ruby', '~> 1.3'
-  spec.add_development_dependency 'minitest', '~> 5.0'
+  spec.add_development_dependency 'minitest', '~> 6.0'
   spec.add_development_dependency 'opentelemetry-test-helpers'
   spec.add_development_dependency 'rake', '~> 13.3'
   spec.add_development_dependency 'rubocop', '~> 1.65'

test_helpers/opentelemetry-test-helpers.gemspec

@@ -25,7 +25,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
   spec.required_ruby_version = '>= 3.3'
 
-  spec.add_development_dependency 'minitest', '~> 5.0'
+  spec.add_development_dependency 'minitest', '~> 6.0'
   spec.add_development_dependency 'opentelemetry-sdk'
   spec.add_development_dependency 'pry'
   spec.add_development_dependency 'pry-byebug' unless RUBY_ENGINE == 'jruby'