获取 git 用户名

@return {string}
function getGitUser() {
    try {
        let name = execSync('git config --get user.name');
        let email = execSync('git config --get user.email');
        name = name && name.toString().trim();
        email = email && ('<' + email.toString().trim() + '>');
        return (name || '') + (email || '');
    }
    catch (e) {
        return '';
    }
}