Support source dependencies

[baszalmstra]

Now that we can build wheels from source distributions, it would be really useful to be able to specify source dependencies. E.g.

foo = { git="https://github.com/foo-bar/foo.git" }

pep508_rs already supports this in requirements.

[burdiyan]

I hope this will also support local sources, not only remote VCS :)

[nichmor]

Hello!
I would like to ask if this issue is free 😊
If yes, would it be possible for me to start working on it?

Thank you!

[wolfv]

@nichmor to my knowledge, no one is working on it :)

Maybe it would be best to start with local path dependencies?

For git dependencies, we could re-use some code we have in rattler-build (where we are using git from the command line to check out a repository).

[nichmor]

@wolfv
Thank you for the suggestion!
Will start with local path first