Support for json schema draft 2020-12

[jwgcooke]

Do you have any plans to support the most recent version of JSON Schema (2020-12)? Base don what I see in the code and the docs there is currently only support for up to draft 09.

[andyglow]

yeah, that would be good to add 2020-12 support
I'm not sure about the timeline thought
if you are willing to contribute, please do
any contribution is appreciated

[jwgcooke]

I am (at best) an entry level on the Scala front, I cloned the repo to start seeing if I could handle anything and ran into #284 ... I am happy to poke at it and see what I can do to help.

[andyglow]

great. thank you

[jwgcooke]

Changes from 09 --> 2020-12

https://json-schema.org/draft/2020-12/release-notes.html