Fix broken link (vercel#14158)

Author: valmassoi

examples/ssr-caching/README.md

@@ -3,7 +3,7 @@
 React Server Side rendering is very costly and takes a lot of server's CPU power for that. One of the best solutions for this problem is cache already rendered pages.
 That's what this example demonstrate.
 
-This app uses Next's [custom server and routing](https://github.com/vercel/next.js#custom-server-and-routing) mode. It also uses [express](https://expressjs.com/) to handle routing and page serving.
+This app uses Next's [custom server and routing](https://nextjs.org/docs/advanced-features/custom-server) mode. It also uses [express](https://expressjs.com/) to handle routing and page serving.
 
 ## How to use