docs: update to Internet Standard reference

README.md

@@ -21,7 +21,7 @@ JSON-C - A JSON implementation in C <a name="overview"></a>
 JSON-C implements a reference counting object model that allows you to easily
 construct JSON objects in C, output them as JSON formatted strings and parse
 JSON formatted strings back into the C representation of JSON objects.
-It aims to conform to [RFC 7159](https://tools.ietf.org/html/rfc7159).
+It aims to conform to [RFC 8259](https://www.rfc-editor.org/rfc/rfc8259).
 
 Skip down to [Using json-c](#using)
 or check out the [API docs](https://json-c.github.io/json-c/),