Support for importing and merging referenced schema

[itsavinash]

Hi There,

I have a use case where I am using the this repo to get a schema from the schema registry which contains another schema as a reference. Is there a way to call the referenced schema and merge it into the main schema? As the https://github.com/flix-tech/schema-registry-php-client/blob/master/src/Registry/PromisingRegistry.php#L142 sends the response to the AvroSchema::parse() method which expects the referenced schema to present within the main schema.

Please let me know if there is an alternative way to do this or if I am missing anything. Thanks