Update thor to v0.18.1

Author: Chris Hunt

github-auth.gemspec

@@ -29,5 +29,5 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'thin',           '~> 1.6.1'
 
   spec.add_runtime_dependency 'httparty', '~> 0.12.0'
-  spec.add_runtime_dependency 'thor',     '~> 0.18'
+  spec.add_runtime_dependency 'thor',     '~> 0.18.1'
 end