Upgrade yard to 0.9.24, CVE and Ruby 2.7 compatible

Yard need Redcarpet upgraded otherwise it can find it

Author: xaviershay

Gemfile

@@ -7,12 +7,12 @@ gemspec
 rspec_dependencies_gemfile = File.expand_path("../Gemfile-rspec-dependencies", __FILE__)
 eval_gemfile rspec_dependencies_gemfile
 
-gem 'yard', '~> 0.8.7', :require => false
+gem 'yard', '~> 0.9.24', :require => false
 
 ### deps for rdoc.info
 group :documentation do
-  gem 'redcarpet',     '2.3.0'
-  gem 'github-markup', '1.0.0'
+  gem 'redcarpet'
+  gem 'github-markup'
   if RUBY_VERSION > '2.0.0'
     gem 'relish'
   end