Function cargo_fetcher::cargo::read_cargo_config

pub fn read_cargo_config(
    cargo_home_path: PathBuf,
    dir: PathBuf
) -> Result<Vec<Registry>>

Reads all of the custom registries configured in cargo config files.

Gathers all of the available .cargo/config(.toml) files, then applies them in reverse order, as the more local ones override the ones higher up in the hierarchy

See https://doc.rust-lang.org/cargo/reference/config.html