[移动开发]flutter打包异常You must have a COPYING LICENSE or UNLICENSE file in the root directory

1. flutter工程打包发布的时候遇到以下问题

You must have a COPYING, LICENSE or UNLICENSE file in the root directory
...
Missing requirements:
* Your pubspec.yaml is missing a "homepage" field.
Sorry, your package is missing a requirement and can't be published yet.
For more information, see: https://www.dartlang.org/tools/pub/cmd/pub-lish.

2. 原因分析：缺少证书导致打包之后发布失败
   

3. 按照上图在根目录添加一个LISCENSE文件，空的即可