Support `$dynamicAnchor` and `$dynamicRef`

[brandonbloom]

These keywords are defined in the JSON Schema 2020-12 dialect.

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

These are useful for representing generics: https://json-schema.org/blog/posts/dynamicref-and-generics

Specification of dynamic scope rules: https://json-schema.org/draft/2020-12/json-schema-core#name-lexical-scope-and-dynamic-s

[daveshanley]

This is the first request for this I have seen, but yes, it should be supported.

[hendrikheil]

I'd love to set a bounty for implementing this feature in libopenapi!
My team and me unfortunately can't tackle this ourselves, but I'd love to contribute to the project through a bounty for the implementation of this feature!

If anybody is interested in tackling this, I'm around on LinkedIn or on the pb33f discord #libopenapi channel 👍