cramjam: wrong `Cargo.lock` used?

[mgorny]

It seems that in cramjam there are Cargo.lock files with conflicting declarations all over the place but Cargo seems to be using the one in workspace directory.

[mgorny]

From a quick glance at cargo code, it seems to use Cargo.lock from workspace root indeed. I suppose our logic needs to be rewritten to look for workspace root independently of Cargo.lock, and use that to determine Cargo.lock location.