Add ruby2_keywords

Author: ydah

spec/rspec/rails/configuration_spec.rb

@@ -273,6 +273,7 @@ def self.application; end
           def welcome(to:)
             mail(to: to, subject: 'subject', body: render(inline: "Hello", layout: false))
           end
+          ruby2_keywords :welcome if respond_to?(:ruby2_keywords, true)
         end
       end