Supporting relative path in Cargo.toml depends

[TotalKrill]

How would one do this, currently I am building the entire workspace, which makes it work, but then other tools doesn't work since they do not support workspaces it seems

[Alexhuszagh]

This is a duplicate of #139.

[Dylan-DPC-zz]

Thanks for opening the issue (and sorry about the delays)

From the readme:

path dependencies (in Cargo.toml) that point outside the Cargo project won't work because cross use docker containers only mounts the Cargo project so the container doesn't have access to the rest of the filesystem.

So right now it wouldn't be possible to make this change without making a major change in how cross works which is beyond our scope at the moment.