Update contributing.md (#16787)

Removed the Gitpod example as it is sunsetting in fall 2025

Author: thomlucc

contributing.md

@@ -35,18 +35,6 @@ Please use the Github issues (after discussing them on the forum) **only** for:
 
 We will try to enforce these rules as we consider the forum is a better place for discussions and learnings.
 
-## Online one-click setup for Contributing
-
-You can use Gitpod (A free online VS Code like IDE) for contributing online. With a single click it'll launch a workspace and automatically:
-
--   clone the BabylonJS repo.
--   install the dependencies.
--   run `npm run start`.
-
-so that you can start straight away.
-
-[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/BabylonJS/Babylon.js)
-
 ## Pull requests
 
 We are not complicated people, but we still have some [coding guidelines](https://doc.babylonjs.com/contribute/toBabylon/approvedNamingConventions/)