Updates docs for #115

Notes what release the new functionality was added in, and clarifies
that it applies to a `GET`-specific input filter.

README.md

@@ -92,7 +92,8 @@ these parameters present in the request will also be used when generating links
 
 Examples of query string arguments you may want to whitelist include "sort", "filter", etc.
 
-Note that if an input filter exists for query params, its keys will be merge with those from configuration
+**Starting in 1.5.0**: if a input filter exists for the `GET` HTTP method, its
+keys will be merged with those from configuration.
 
 ##### Sub-key: `controller_class` (optional)