Composer 镜像服务地址修改

进入 composer.json 文件所在目录执行以下命令（表示只改变当前项目的 composer 镜像服务）：

composer config repo.packagist composer https://packagist.phpcomposer.com

执行完后，composer.json 文件将变为：

{
    ......
    "repositories": {
        "packagist": {
            "type": "composer",
            "url": "https://packagist.phpcomposer.com"
        }
    }
}