Support has now landed on nightly for Cargo to support replaced sources which primarily includes the ability to vendor dependencies. More documentation and information can be found online and in the associated PR, but if you’d like to give it a spin, you can try out:
$ cargo install cargo-vendor $ cd path/to/project $ cargo vendor
And you should be good to go! Note that this requires a nightly version of Cargo right now, and rustup is a great way to get it!
If you’ve got any problems, feel free to either ask here or open an issue!