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

I guess where the deprecation metadata is actually stored can be flexible.

However, regardless of where it is stored, I think it's important (in the user-facing side) that crate authors and maintainers don't have to go through any hoops or login to any 3rd-party services just to deprecate a package/version.

The crate author/maintainer should be able to run cargo deprecate <PKG_NAME>[@<VERSION_RANGE>] -m <REASON> as long as they have valid token on their ~/.cargo/credentials.toml.

Alternatively, they can just deprecate the packages/versions on the web UI of crates.io.