laravel5.5 composer 不下来 ，求解决

[Joken2]

[vagrant@localhost share]$ composer require "yangyifan/upload:v0.2"
./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
- Installation request for yangyifan/upload v0.2 -> satisfiable by yangyifan/upload[v0.2].
- Conclusion: don't install qiniu/php-sdk v7.2.2
- yangyifan/upload v0.2 requires qiniu/php-sdk v7.0.* -> satisfiable by qiniu/php-sdk[v7.0.0, v7.0.2, v7.0.3, v7.0.4, v7.0.5, v7.0.6, v7.0.7, v7.0.8].
- Can only install one of: qiniu/php-sdk[v7.0.0, v7.2.2].
- Can only install one of: qiniu/php-sdk[v7.0.2, v7.2.2].
- Can only install one of: qiniu/php-sdk[v7.0.3, v7.2.2].
- Can only install one of: qiniu/php-sdk[v7.0.4, v7.2.2].
- Can only install one of: qiniu/php-sdk[v7.0.5, v7.2.2].
- Can only install one of: qiniu/php-sdk[v7.0.6, v7.2.2].
- Can only install one of: qiniu/php-sdk[v7.0.7, v7.2.2].
- Can only install one of: qiniu/php-sdk[v7.0.8, v7.2.2].
- Installation request for qiniu/php-sdk (locked at v7.2.2) -> satisfiable by qiniu/php-sdk[v7.2.2].

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

[Qsnh]

可能是你的项目下已经安装了qiniu的扩展包然后在安装这个包，这个包要求安装的是七牛7.0.*的版本，所以就导致冲突了，你可以这样解决：卸载掉项目中骑牛包，安装7.0.*的版本