Added VS Code Badge (#3840)

User can click the badge to open on VS Code directly

Co-authored-by: REJack <info@rejack.de>

README.md

@@ -4,6 +4,7 @@
 [![Packagist](https://img.shields.io/packagist/v/almasaeed2010/adminlte.svg)](https://packagist.org/packages/almasaeed2010/adminlte)
 [![cdn version](https://data.jsdelivr.com/v1/package/npm/admin-lte/badge)](https://www.jsdelivr.com/package/npm/admin-lte)
 [![Gitpod Ready-to-Code](https://img.shields.io/badge/Gitpod-Ready--to--Code-blue?logo=gitpod)](https://gitpod.io/from-referrer/)
+[![Open in Visual Studio Code](https://open.vscode.dev/badges/open-in-vscode.svg)](https://open.vscode.dev/ColorlibHQ/AdminLTE)
 [![Discord Invite](https://img.shields.io/badge/discord-join%20now-green)](https://discord.gg/jfdvjwFqfz)
 
 **AdminLTE** is a fully responsive administration template. Based on **[Bootstrap 4.6](https://getbootstrap.com/)** framework and also the JS/jQuery plugin.