Add support for `ajv/dist/2020` that targets `https://json-schema.org/draft/2020-12/schema`

[finom]

Is your feature request related to a problem? Please describe.
Currently the resolver supports draft-07 but draft-2020-12 (also used by default at Zod 4 toJSONSchema) requires to use another module imported from ajv/dist/2020

import Ajv from 'ajv/dist/2020';

Describe the solution you'd like
Not sure how it's going to work: it either can be another feature of existing AJV resolver with some conditions, or a different resolver.

Thanks!