安装不上呢

[Sdlearn]

提示如下信息：
./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
- Can only install one of: laravel/framework[v5.6.17, 5.5.x-dev].
- Can only install one of: laravel/framework[5.5.x-dev, v5.6.17].
- Can only install one of: laravel/framework[5.5.x-dev, v5.6.17].
- dominator88/laravel-smart dev-master requires laravel/framework 5.5.* -> satisfiable by laravel/framework[5.5.x-dev].
- Installation request for dominator88/laravel-smart dev-master -> satisfiable by dominator88/laravel-smart[dev-master].
- Installation request for laravel/framework (locked at v5.6.17, required as 5.6.*) -> satisfiable by laravel/framework[v5.6.17].

[alibaba]

请使用 laravel 5.5