Вы можете изменить generateLoaders
на
function generateLoaders (loader, loaderOptions) {
const loaders = [cssLoader]
if (loader) {
loaders.push({
loader: loader + '-loader',
options: Object.assign({}, loaderOptions, {
sourceMap: options.sourceMap
})
})
}
// Extract CSS when that option is specified
// (which is the case during production build)
if (options.extract) {
return [MiniCssExtractPlugin.loader].concat(loaders)
} else {
return ['vue-style-loader'].concat(loaders)
}
}