Laravel安装程序v1.4.1与PHP 7.1软件包不兼容

我无法在新鲜' pop！_OS '（基于 ubuntu 17.10 <， pop！/strong> by System76）Linux Istalation。

找不到如何'删除Symfony/Console V4.0.1 '。那么谁能帮助我解决这种烦恼？

我遵循https://www.youtube.com/watch?v=b38muodc1l4本教程，一切都变得完美，直到 Composer Global需要" Laravel/installer" 命令。

输入此命令后，终端中的结果为：

    Changed current directory to /home/chakra/.config/composer
Using version ^1.4 for laravel/installer
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
  Problem 1
    - Conclusion: don't install laravel/installer v1.4.1
    - Conclusion: remove symfony/console v4.0.1
    - Installation request for laravel/installer ^1.4 -> satisfiable by laravel/installer[v1.4.0, v1.4.1].
    - Conclusion: don't install symfony/console v4.0.1
    - laravel/installer v1.4.0 requires symfony/console ~2.3|~3.0 -> satisfiable by symfony/console[v2.3.0, ..., v3.4.1].
    - Can only install one of: symfony/console[v3.0.0, v4.0.1].
    ...
    - Can only install one of: symfony/console[v2.8.9, v4.0.1].
    - Installation request for symfony/console (locked at v4.0.1) -> satisfiable by symfony/console[v4.0.1].

Installation failed, reverting ./composer.json to its original content.
➜  Sites 

composer.json /home/chakra/.config/composer（默认情况下的所有内容都没有像视频教程那样更改）

sudo nano composer.json之后：

{
    "require": {
        "cpriego/valet-linux": "^2.0"
        }
}

作曲家，NPM，NGINX版本：

➜  ~ which composer
/usr/local/bin/composer
➜  ~ composer --version
Composer version 1.5.5 2017-12-01 14:42:57
➜  ~ npm --version
5.5.1
➜  ~ nginx -v
nginx version: nginx/1.12.1 (Ubuntu)
➜  ~