Reference latest OAS versions

[dret]

It would be good to reference the latest published versions of OAS (both published in October 2024):

• OAS 3.0: https://spec.openapis.org/oas/v3.0.4.html
• OAS 3.1: https://spec.openapis.org/oas/v3.1.1.html

[ioggstream]

@dret If we want to follow the "OAS 2.0 too" path, I think we should:

• not mention every possible release;
• just reference the OAS website;
• improve the interoperability considerations section.

WDYT?

cc: @handrews