Add support for Draft 2020-12

[heynan0]

Specification

http://json-schema.org/specification-links.html#2020-12

Identifier

{ "$schema": "https://json-schema.org/draft/2020-12/schema" }

Reference (based on this):

The identifier for Draft 2019-09 is https://json-schema.org/draft/2019-09/schema.

https://json-schema.org/understanding-json-schema/reference/schema.html#id4

[brandur]

This is definitely a good idea, but to be honest, I'm not sure that I'll get around to it — I'm not using this project anymore, and there are better maintained JSON schema packages out there where people can go to get more modern versions of the spec.

[sandstrom]

For people looking, there is also this gem that is up to date and support the recent draft:

https://github.com/davishmcclurg/json_schemer