Supporting uuid as format?

[goloroden]

The JSON schema specification does not know of a uuid format for strings, however some other validators (such as ajv support it, and to be honest, it is pretty useful 😉

Would you mind adding support for uuid as format? I think since it is well defined what a UUID is, this should be quite easy to implement, and it would make using jjv even much more enjoyable than it already is 😊

If you are fine with this, I can happily come up with a PR.

What do you think?