fn look_for_cargo_manifest(base: &Path) -> Result<Option<PathBuf>> {
    Ok(if base.is_dir() {
        let base = base.join("Cargo.toml");
        if base.is_file() {
            let base = base.canonicalize()?;
            log::debug!("Using {} manifest as anchor file", base.display());
            Some(base)
        } else {
            log::debug!("Cargo manifest files does not exist: {}", base.display());
            None
        }
    } else if let Some(file_name) = base.file_name() {
        if file_name == "Cargo.toml" && base.is_file() {
            let base = base.canonicalize()?;
            log::debug!("Using {} manifest as anchor file", base.display());
            Some(base)
        } else {
            log::debug!("Cargo manifest files does not exist: {}", base.display());
            None
        }
    } else {
        log::debug!(
            "Provided parse target is neither file or dir: {}",
            base.display()
        );
        None
    })
}
Try to find a cargo manifest, given a path, that can either be a directory
or a path to a manifest.
src/config/args.rs