执行 composer --version 命令的时候报 Your requirements could not be resolved to an installable set of packages. 错误

Your requirements could not be resolved to an installable set of packages.

以上原因：不匹配composer.json要求的版本。

解决方案：

composer可以设置忽略版本匹配，

composer install --ignore-platform-reqs

composer update --ignore-platform-reqs
再次执行composer命令可以正常安装包了。