pub fn new() -> Self {
        let mut inner = cargo_metadata::MetadataCommand::new();
        // Always use --all-features so that we get a full view of the graph.
        inner.features(CargoOpt::AllFeatures);
        Self { inner }
    }
Creates a default `cargo metadata` command builder.

By default, this will look for `Cargo.toml` in the ancestors of this process's current
directory.
guppy/src/metadata_command.rs