message: Bug Generate unique CSS filenames
  Avoids the error: Multiple assets emit different content to the same filename
diff: @@ -32,7 +32,8 @@ const WDS_PORT = 8080;
  /* Helpers */
  const extractCSS = new MiniCssExtractPlugin({
  - filename: 'app-bundle.[contenthash].css',
  + filename:
  + NODE_ENV === 'production' ? 'app-bundle.[contenthash].css' : 'app-bundle.[name].[hash].css',
  // We follow BEM naming to scope CSS.
  // See https://github.com/webpack-contrib/mini-css-extract-plugin/issues/250
  ignoreOrder: true,
  