Specify supported JSON Schema version

[janlucaklees]

I would love to see the actual JSON Schema version that is supported by the library somewhere in the readme. Sure I can go look in the tests and infer that only Draft-4 of the JSON Schema is supported, but you need to be very desperate to do that.

Context: I spent a whole lot of time figuring out why 'contains' is not working for an array. Not sure, but maybe with Constraint::CHECK_MODE_VALIDATE_SCHEMA set, it should warn you about properties in your JSON Schema that are not supported.

I would be open to "implement" those changes myself and open a PR for them to be merged.

[erayd]

Good suggestion. A PR for this would be appreciated :-).

[yannickroger]

@erayd @janlucaklees I think we can close that one 😉

[janlucaklees]

@yannickroger Yess, thank you for reminding me!