yii2 - 如何修改他人在github.com上的源码

使用yii2 安装了这个扩展 https://github.com/hguenot/yii2-gftp，可里面很多错误，修改了，想提交到github.com，如何操作。

已经fork了一个g9901/yii2-gftp，然后把 yii2项目的 basic/composer.json 对应的require 改为了g9901/yii2-gftp，可更新 composer update g9901/yii2-gftp -vvv，却所有的全部都更新了。而且，到最后还是无法更新这个组件，提示如下：

  Problem 1
    - The requested package g9901/yii2-gftp could not be found in any version, t
here may be a typo in the package name.

Potential causes:
 - A typo in the package name
 - The package is not available in a stable-enough version according to your min
imum-stability setting
   see <https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion>; f
or more details.

Read <https://getcomposer.org/doc/articles/troubleshooting.md>; for further commo
n problems.

D:\website\flxx2\basic>