Pin Minitest to < 6 for minitest/mock

Author: evgeni

kafo.gemspec

@@ -20,7 +20,7 @@ Gem::Specification.new do |spec|
   spec.required_ruby_version = '>= 2.7'
 
   spec.add_development_dependency 'bundler', '>= 1.3', '< 3'
-  spec.add_development_dependency 'minitest'
+  spec.add_development_dependency 'minitest', '< 6'
   spec.add_development_dependency 'minitest-reporters'
   spec.add_development_dependency 'rake'
   spec.add_development_dependency 'simplecov'