Pin next and vercel packages and deprecate next-on-pages in favour of open-next (#986)

* pin `next` and `vercel` dependencies

* add deprecation banner to main readme

---------

Co-authored-by: Victor Berchet <[email protected]>
Co-authored-by: James Anderson <[email protected]>

Author: 3 people

.changeset/silver-jars-develop.md

@@ -0,0 +1,5 @@
+---
+'@cloudflare/next-on-pages': patch
+---
+
+Deprecate package and pin `next` and `vercel` peer dependencies

README.md

@@ -1,10 +1,19 @@
+> [!WARNING]
+>
+> > <p align="center">⚠️ 🚧 ⚠️</p>
+>
+> The next-on-pages package is deprecated, if you want to deploy a Next.js application on Cloudflare, please use the [OpenNext Cloudflare adapter](https://opennext.js.org/cloudflare) instead.
+> If you have a Next.js application that already uses next-on-pages the [OpenNext getting started guide for existing applications](https://opennext.js.org/cloudflare/get-started#existing-nextjs-apps) presents instructions on how to migrate to the OpenNext adapter.
+>
+> > <p align="center">⚠️ 🚧 ⚠️</p>
+
 <p align="center">
   <h1 align="center">⚡▲ <code>@cloudflare/next-on-pages</code> ▲⚡</h1>
 
   <p align="center">Build, develop, and deploy Next.js apps for Cloudflare Pages.</p>
 </p>
 
-> [!NOTE]  
+> [!NOTE]
 > The best way to run Next.js apps on Cloudflare is to use [`@opennextjs/cloudflare`](https://opennext.js.org/cloudflare). If you're coming from Vercel, you can migrate your Next.js app easily using [Diverce](https://github.com/ygwyg/diverce), which can also help you migrate from `@cloudflare/next-on-pages`
 
 `@cloudflare/next-on-pages` is a CLI tool that you can use to build and develop [Next.js](https://nextjs.org/) applications so that they can run on the [Cloudflare Pages](https://pages.cloudflare.com/) platform.