document usage of writeToFileEmit with webpack-clean plugin

[devkral]

• Manifest Plugin Version:
  3.1.1

Documentation Is:

• Missing
• Needed
• Confusing
• Not Sure?

Please Explain in Detail...

webpack-clean plugin deletes manifest.json if used with webpack-dev-server.
It should be documented that you have to exclude manifest.json like this

new CleanWebpackPlugin({
            verbose: true,
//important elsewise minifest.json is deleted
            cleanOnceBeforeBuildPatterns: ['**/*', '!manifest.json'],
        }),

[shellscape]

Thanks, I'll add this to the README.

[gaurav5430]

Thanks, this saved me from opening a new issue for manifest not being generated with webpack-dev-server