update external dereferencing note

Author: mattpolzin

README.md

@@ -339,7 +339,7 @@ try encodeEqual(URL(string: "https://website.com"), AnyCodable(URL(string: "http
 
 ### Dereferencing & Resolving
 #### External References
-This is currently only available for OAS 3.1 documents (supported by the `OpenAPIKit` module (as opposed to the `OpenAPIKit30` moudle). External dereferencing does not resolve any local (internal) references, it just loads external references into the Document. It does this by storing any loaded externally referenced objects in the Components Object and transforming the reference being resolved from an external reference to an internal one. That way, you can always run internal dereferencing as a second step if you want a fully dereferenced document, but if you simply wanted to load additional referenced files then you can stop after external dereferencing.
+External dereferencing does not resolve any local (internal) references, it just loads external references into the Document. It does this by storing any loaded externally referenced objects in the Components Object and transforming the reference being resolved from an external reference to an internal one. That way, you can always run internal dereferencing as a second step if you want a fully dereferenced document, but if you simply wanted to load additional referenced files then you can stop after external dereferencing.
 
 OpenAPIKit leaves it to you to decide how to load external files and where to store the results in the Components Object. It does this by requiring that you provide an implementation of the `ExternalLoader` protocol. You provide a `load` function and a `componentKey` function, both of which accept as input the `URL` to load. A simple mock example implementation from the OpenAPIKit tests will go a long way to showing how the `ExternalLoader` can be set up: