Update link to Recipes documentation in Readme (#294)

Update URI in Readme to appropriate Recipes documentation

Author: jarrettgreen

README.md

@@ -31,7 +31,7 @@ end
 ## Documentation
 
 - [API](https://ruby-doc.org/stdlib/libdoc/csv/rdoc/CSV.html):  all classes, methods, and constants.
-- [Recipes](https://ruby-doc.org/core/doc/csv/recipes/recipes_rdoc.html):  specific code for specific tasks.
+- [Recipes](https://ruby.github.io/csv/doc/csv/recipes/recipes_rdoc.html):  specific code for specific tasks.
 
 ## Development