Add WinGet command to README

Author: Trenly

README.md

@@ -39,6 +39,11 @@ If you have access to GitHub Copilot via your organization or enterprise, you ca
 
 ### Installation
 
+Install with [WinGet](https://github.com/microsoft/winget-cli):
+```bash
+winget install GitHub.Copilot
+```
+
 Install globally with npm:
 
 ```bash