composer下载提示
Warning from https://mirrors.aliyun.com/composer: You are using an outdated version of Composer. Composer 2.0 is now available and you should upgrade. See https://getcomposer.org/2
原因：从报错信息可以看出是composer版本太旧的。
解决办法：升级本地的composer版本
composer self-update
