Request: Provide an official way to *deprecate* a crate. NOT yank. Yank is stupid

This could be resolved by a deeper integration with the RustSec database which already has unmaintained advisories. crates.io already pulls RustSec security advisories (indirectly through GithHub, but still), so I think it could be improved further. In other words, this metadata does not have to be part of the crates.io registry.