Proposal: Update `dataset_description.Authors` requirement level to RECOMMENDED

[effigies]

The validator has been warning on the absence of the authors field for a while, so from the perspective that OPTIONAL, RECOMMENDED, REQUIRED correspond to silence, warnings and errors in validation, it has been RECOMMENDED. I suggest that for consistency we formally mark Authors as RECOMMENDED in the spec.

This will not invalidate any datasets or modify validation behavior in any way.

Thoughts?

[sappelhoff]

I agree ✔️

[Remi-Gau]

Same