Update getpublicpath.mdx (#3806)

Author: SuAutumn

apps/website-new/docs/en/configure/getpublicpath.mdx

@@ -13,6 +13,10 @@ In the example below, `getPublicPath` is set. When other consumers load this pro
 ```getPublicPath``` Must be a function as a string.
 :::
 
+:::tip NOTE
+If you're using module federation webpack plugin and want to set a dynamic publicPath, you should set `__webpack_public_path__ = window.cdn_prefix` statement in `getPublicPath` function body.
+:::
+
 ```ts title="rspack.config.ts"
 module.exports = {
   plugins: [