Apply suggested fix to CONTRIBUTING.md from Copilot Autofix

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

Author: neatudarius

CONTRIBUTING.md

@@ -35,7 +35,7 @@ This project includes a development container configuration for VS Code. To use
 ```shell
 $ sudo apt install nodejs
 $ sudo apt install npm
-$ npm install yarn
+$ npm install -g yarn
 ```
 
 </details>