Compatibility problem with Razzle 3

[suciudan]

Hello.

It looks like the plugin is not compatible with Razzle 3 (or maybe I'm missing something).

I followed the steps from the README. The files are compressed (both br and gz) but the loaded files on the page are the uncompressed ones.

I noticed inside assets.json, the compressed files are stored under an empty key name:

"": {
    "json": "/..\\chunks.json",
    "css": [
        ...
    ],
    ...
}

I made a sample repository here.

Thank you!