feat: update thor dependancy

Author: guppy0356

pact-message.gemspec

@@ -34,7 +34,7 @@ Gem::Specification.new do |spec|
   # and Pact::ConsumerContractWriter. Potentially we should extract
   # or duplicate these classes to remove the pact-mock_service dependency.
   spec.add_runtime_dependency "pact-mock_service", "~> 3.1"
-  spec.add_runtime_dependency "thor", "~> 0.20"
+  spec.add_runtime_dependency "thor", '>= 0.20', '< 2.0'
 
   spec.add_development_dependency "rake", "~> 12.3", ">= 12.3.3"
   spec.add_development_dependency "rspec", "~> 3.0"