doc: updating link to website documentation for frontend

Author: omosola

app/README.md

@@ -1,6 +1,6 @@
 # OpenML Website
 
-See https://docs.openml.org/Website/ for instructions on the current (React) app.
+See https://docs.openml.org/contributing/website/Website/ for instructions on the current (React) app.
 For the new (Next.js) app, see below.
 
 This is a [Next.js](https://nextjs.org/) project bootstrapped with [`create-next-app`](https://github.com/vercel/next.js/tree/canary/packages/create-next-app).