Function run_git_command 

pub async fn run_git_command<I, S>(
    args: I,
    current_dir: Option<&PathBuf>,
) -> Result<String, DownloadError>
where
    I: IntoIterator<Item = S> + Clone,
    S: AsRef<OsStr>,

Run a git command with the given arguments in the given directory.

The function output is parsed as a UTF-8 string and returned.