如果php未安装扩展xml，可能会出现如下错误。
Composer detected issues in your platform: Your Composer dependencies require the following PHP extensions to be installed: xml
解决办法
apt install php7.4-xml
如果php未安装扩展xml，可能会出现如下错误。
Composer detected issues in your platform: Your Composer dependencies require the following PHP extensions to be installed: xml
解决办法
apt install php7.4-xml