查看当前的镜像源：
composer config -g -l repo.packagist
切换国内镜像
阿里云（推荐）
composer config -g repos.packagist composer https://mirrors.aliyun.com/composer/
华为云（更新慢一些）
composer config -g repos.packagist composer https://repo.huaweicloud.com/repository/php/
腾讯云（不推荐）
composer config -g repos.packagist composer https://mirrors.cloud.tencent.com/composer/
