Walter Cloete

HTTP Relative URL support in $ref

1

## Expected Behaviour The [OpenAPI 3.0 spec](https://spec.openapis.org/oas/v3.0.0#relative-references-in-urls) supports relative URLs in `$ref` definitions, but currently this ends up in a call to [`util.url.absurl`](https://github.com/RonnyPfannschmidt/prance/blob/36ea4364588df66b20467561463a3c35f3e8d104/prance/util/url.py#L31) which specifies that > Non-file URLs are...