Issues with custom webpack loader with Kotlin/JS

I know that we can override webpack config in webpack.config.d directory. So for including LESS style sheets, I placed a file in that directory:

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

    test: /\.(le|c)ss/,
    use: [

Now, webpack complains about missing dependencies. I know we can declare dependencies with implementation(npm("project-name")), but how can I declare a dev-dependency?

It can be done since 1.4 release (

Until 1.4.0 is not released, you can try 1.4.0-rc (