PWA not work in windows

[VdustR]

This might be related to micromatch/is-glob#9

In linux it works fine. In windows it throw:

[copy-webpack-plugin] WARNING - unable to locate 'C:\my-repo\{manifest,manifest}.json'

I checked copy-webpack-plugin and it returned false here only in windows.

Tried:

> require('is-glob')('C:\\{foo,bar}.js')
false
> require('is-glob')('/{foo,bar}.js')
true

I also tried is-glob@2.0.1 and got true in both cases.

Any idea to fix this?

Thanks for the great repo.

[egoist]

I think we can convert back slash to slash here to fix this. PR welcome.