Update Minitest documentation (5.7.0)

lib/docs/scrapers/rdoc/minitest.rb

@@ -2,8 +2,11 @@ module Docs
   class Minitest < Rdoc
     self.name = 'Ruby / Minitest'
     self.slug = 'minitest'
-    self.version = '5.6.0'
+    self.version = '5.7.0'
     self.dir = '/Users/Thibaut/DevDocs/Docs/RDoc/Minitest' # rake docs
+    self.links = {
+      code: 'https://github.com/seattlerb/minitest'
+    }
 
     html_filters.replace 'rdoc/entries', 'minitest/entries'