Class 'prawee\uploadify\Uploadify' not found

在yii2中使用uploadify过程中发现的问题，网上g%b没发现解决办法，有的说psr缘故，求解？
还有composer安装不上。所以只能git checkout,

composer提示：

Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - The requested package prawee/yii2-uploadify could not be found in any vers
ion, there may be a typo in the package name.
  Problem 2
    - The requested package yrssoft/yii2-kindeditor could not be found in any ve
rsion, there may be a typo in the package name.

求解

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简单看了下这两个仓库，推测是因为这两个仓库都没有release版本，所以才提示找不到。
所以解决方案可以是：

1. 手动指定版本为 dev-master.例如： composer require prawee/yii2-uploadify=dev-master
2. 修改的的composer.json,添加： "minimum-stability": "dev"