docker php80 安装composer

php -r "copy('https://install.phpcomposer.com/installer', 'composer-setup.php');"
php composer-setup.php

#All settings correct for using Composer
#Downloading...

#Composer (version 2.6.5) successfully installed to: //composer.phar
#Use it: php composer.phar

# 移动 composer.phar，这样 composer 就可以进行全局调用：
mv composer.phar /usr/local/bin/composer

#切换为国内镜像：
composer config -g repo.packagist composer https://mirrors.aliyun.com/composer/

#查看composer版本
composer -v

#更新至最新版本
composer selfupdate