Extend the draft to define a new grant type

[Sakurann]

Can this draft be extended to define a new grant type urn:ietf:params:oauth:client-assertion-type:jwt-client-attestation where a sender-constrained JWT can be used to request an Access Token? for example, i think it would be useful in use-cases like catena-x eclipse-dataspace-dcp/decentralized-claims-protocol#34 (cc @c2bo)
Inspiration for the suggestion is https://www.rfc-editor.org/rfc/rfc7523, which defined urn:ietf:params:oauth:grant-type:jwt-bearer both for client authentication and a new grant type.

[tplooker]

@Sakurann can you please elaborate on the usecase here, the attached issue doesn't provide any context.