Add Open VSX badge to readme

Author: Rpinski

README.md

@@ -1,4 +1,4 @@
-# ILSpy Visual Studio Code Extension [![Visual Studio Marketplace](https://img.shields.io/visual-studio-marketplace/v/icsharpcode.ilspy-vscode)](https://marketplace.visualstudio.com/items?itemName=icsharpcode.ilspy-vscode) [![Join the chat at https://gitter.im/icsharpcode/ILSpy](https://badges.gitter.im/icsharpcode/ILSpy.svg)](https://gitter.im/icsharpcode/ILSpy?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) [![CI](https://github.com/icsharpcode/ilspy-vscode/actions/workflows/ci.yml/badge.svg)](https://github.com/icsharpcode/ilspy-vscode/actions/workflows/ci.yml)
+# ILSpy Visual Studio Code Extension [![Visual Studio Marketplace](https://img.shields.io/visual-studio-marketplace/v/icsharpcode.ilspy-vscode?label=VS%20Marketplace)](https://marketplace.visualstudio.com/items?itemName=icsharpcode.ilspy-vscode)  [![Open VSX](https://img.shields.io/open-vsx/v/icsharpcode/ilspy-vscode?label=Open%20VSX&color=blue)](https://open-vsx.org/extension/icsharpcode/ilspy-vscode) [![Join the chat at https://gitter.im/icsharpcode/ILSpy](https://badges.gitter.im/icsharpcode/ILSpy.svg)](https://gitter.im/icsharpcode/ILSpy?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) [![CI](https://github.com/icsharpcode/ilspy-vscode/actions/workflows/ci.yml/badge.svg)](https://github.com/icsharpcode/ilspy-vscode/actions/workflows/ci.yml)
 
 The ILSpy extension for VS Code is an implementation of ILSpy .NET assembly browser and decompiler running inside of Visual Studio Code UI - in contrast to the [ILSpy desktop application](https://github.com/icsharpcode/ILSpy) running standalone on Windows systems.