docs: fix typo for esModule (#473)

Co-authored-by: Evilebot Tnawi <evilebottnawi@users.noreply.github.com>

Author: yuheiy

README.md

@@ -570,7 +570,7 @@ module.exports = {
     rules: [
       {
         test: /\.css$/i,
-        loader: 'css-loader',
+        loader: 'style-loader',
         options: {
           esModule: true,
         },