Add support for OpenAPI v3.1

[sisp]

OpenAPI v3.1 was released today: https://www.openapis.org/blog/2021/02/18/openapi-specification-3-1-released

It comes with some great improvements. Are there plans to add support for the new specification?

[p1c2u]

jsonschema must get support for v2020-12 draft first

python-jsonschema/jsonschema#782

[alanbchristie]

Do we have an expectation as to when we can expect support for 3.1? I guess it's still stuck by the jsonschema issue?