Go handles this well, kind of. It's super easy (in fact, transparent) to import from GitHub urls. You can self-host your Go packages, but it involves making and hosting some manifest files. Not as seamless as using GitHub, but still totally doable.
Aren't all the ones in the actual Go registry mirrored, though? I thought I read that. They also make it trivial to vendor dependencies, idk if Crates handles that
