next.js

49ef9782 - updated the example of custom-routes-proxying to utilize the App Router (#68941)

updated the example of custom-routes-proxying to utilize the App Router (#68941) This PR updates the custom-routes-proxying example to use the App Router. Here are the changes that have been made: - Renamed the "pages" folder to the "app" folder. - Updated the routing for /, /about & /hello/[slug] files to align with the App Router. - Added the layout.tsx file as part of the App Router. - Updated the package.json file. - Updated the Readme file. CC: @samcx --------- Co-authored-by: Lee Robinson <me@leerob.io> Co-authored-by: samcx <sam@vercel.com>