Support for detecting changes in webhooks

It would be nice to support API changes in webhooks defined with OpenAPI 3.1, in particular:

1. Detect if a webhook is removed
2. Detect changes in the webhook payload

Unfortunately it looks like now this is not possible.

This can be reproduced by doing:

    String oldSpec = Paths.get("webhook1.yml").toUri().toString();
    String newSpec = Paths.get("webhook2.yml").toUri().toString();

    ChangedOpenApi diff = OpenApiCompare.fromLocations(oldSpec, newSpec);

The content of boths specs are attached here (as .txt but they are .yml specs)

webhook1.txt

webhook2.txt

Note that no differences are found in this case

Inizia eseguendo la riproduzione di OpenApiCompare.fromLocations con le specifiche allegate webhook1.txt e webhook2.txt. Traccia il modo in cui vengono confrontati i webhook di OpenAPI 3.1, quindi verifica che la rimozione di un webhook e la modifica del suo payload vengano segnalate come differenze. Il lavoro è completato quando entrambi i casi producono differenze per le specifiche fornite.