Add experimental option to generate dependencies labels against an external repository

[hborawski]

Rather than have all dependency labels be absolute (//Pods/SomePod) this experimental option generates labels to point to an external repository, allowing a more flexible folder structure, since your Pods folder doesn't need to be in the root

//Pods/SomePod -> @Pods//SomePod

This obviously needs to work in conjunction with a repository rule, which I have a basic implementation of that works, if theres a place I can PR that to, I'd be happy to do that

just trying to utilize this plugin for my situation without needing to maintain a fork

The project i'm working on is a multi platform mono-repo, so we want to be able to isolate the ios files into an ios folder, rather than polluting the root of the repo with pod related files

[hborawski]

Build seems to have failed xcode-select, unrelated to my changes

[chenxiao0228]

@hborawski Thanks for the PR!

GitHub upgraded the Mac hosts for running actions, Xcode 12.2 is not valid any more. I'll look into it soon.

[justinseanmartin]

There is another PR up in which @gyfelton removes that check. I think once that lands we can rebase on top of that.

[chenxiao0228]

@hborawski please merge the main branch, it should have been fixed now.