OpenAPI media type

[cportele]

Previously it was planned by OAI to register application/openapi+json (which we use in the current draft), but OAI seems to have changed its mind. See the latest entries in OAI/OpenAPI-Specification#110 which suggest:

• application/vnd.oai.openapi (YAML variant)
• application/vnd.oai.openapi+json (JSON only variant)

As these media types are not registered with IANA yet, I think we should keep the current media type for now, but update it once it has been registered with IANA.

[cmheazel]

Ref: [https://github.com/OAI/OpenAPI-Specification/issues/110](OpenAPI Issue 110)

The MIME Types for OpenAPI have been finalized.
application/vnd.oai.openapi (YAML variant)
application/vnd.oai.openapi+json (JSON only variant)

With an optional version:
application/vnd.oai.openapi;version=3.0

[cportele]

The media types have been agreed by the OAI TSC, but are not yet in the media type register of IANA. However, since they are in the vnd branch, it should not take long. I will create a pull request once the media types are in the IANA register.

[cmheazel]

It would be helpful if we included the media types that the TSC did agree to. The risk is that since they have not been registered, the TSC could change their minds.

[cportele]

It is unclear when or if OAI will register the media types. For now we will use latest ones agreed by the TSC and add a note about their status.

[cportele]

New activity wrt media types: https://www.ietf.org/archive/id/draft-polli-rest-api-mediatypes-00.html