方法一 安装器安装：缺点不能安装指定版本
composer global require "laravel/lumen-installer"
lumen new blog
composer global require "laravel/laravel-installer"
laravel new blog
方法二 ：安装指定版本
composer create-project --prefer-dist laravel/lumen lumen55 '5.6.*'
composer create-project --prefer-dist laravel/laravel blog 5.6.*
如果报错插件
composer create-project --prefer-dist --no-plugins laravel/lumen lumen5 '5.6.*'