配置镜像方法：
阿里云镜像：composer config -g repo.packagist composer https://mirrors.aliyun.com/composer/ 腾讯云镜像：composer config -g repos.packagist composer https://mirrors.cloud.tencent.com/composer/
中国常用composer 镜像：https://learnku.com/composer/wikis/30594
原文：https://www.cnblogs.com/fogwang/p/11410055.html