Updated link to DRF OrderingFilter

Author: mtnntn

docs/usage.md

@@ -135,7 +135,7 @@ simply don't use this filter backend.
 #### OrderingFilter
 
 `OrderingFilter` implements the [JSON:API `sort`](http://jsonapi.org/format/#fetching-sorting) and uses
-DRF's [ordering filter](http://django-rest-framework.readthedocs.io/en/latest/api-guide/filtering/#orderingfilter).
+DRF's [ordering filter](https://www.django-rest-framework.org/api-guide/filtering/#orderingfilter).
 
 Per the JSON:API specification, "If the server does not support sorting as specified in the query parameter `sort`,
 it **MUST** return `400 Bad Request`." For example, for `?sort=abc,foo,def` where `foo` is a valid