Feature description:
[(buf.validate.field).bytes.uuid = true] checks to see if

Problem it solves or use case:
Multiple sources debate how UUIDs should be stored in protocol buffers.

Proposed implementation or solution:
Replicate the functionality of string.uuid for bytes.

Contribution:
I'm taking a pass at it, will update this ticket if I end up getting stuck and run out time.

Examples or references:
n/a

Additional context:
n/a