Support invoking in Cargo Workspaces

[antoniusnaumann]

Invoking in a workspace should execute the command for all members of this workspace that contain a Cargo Swift config.

This issue needs #5 and #6 to be resolved

[antoniusnaumann]

Alternative: Add metadata tag to workspace that specifies which libraries should be built when cargo swift is invoked in a workspace

[antoniusnaumann]

The following behavior will be implemented:

cargo swift package will invoke cargo metadata to detect all crates in the current workspace that have a dependency on UniFFI. The package command is then invoked for every of those crates that are at the same level, above or below the current working directory (but not paralell to it).

This means:
It is possible to invoke cargo swift package in a sub-directory e.g. src/ or the top-level directory of a crate, this will package the current crate. This mirrors the current behavior. But it will also be possible to invoke cargo swift package in a workspace, in which case all crates in the workspace that depend on UniFFI will be packaged.

[antoniusnaumann]

Reopening this as it introduced unwanted behavior for workspaces that contain a root package, if only the root package should be packaged.

[Eliot00]

Can cargo-swift support cargo swift package -p <pname> like cargo build -p does?

[antoniusnaumann]

Can cargo-swift support cargo swift package -p <pname> like cargo build -p does?

That's the solution I currently favor, but I currently don't have time to implement this unfortunately.