doc: Update README.

Author: freezy

README.md

@@ -1,8 +1,10 @@
 # URP for Visual Pinball Engine
 
+[![UPM Package](https://img.shields.io/npm/v/org.visualpinball.engine.unity?label=org.visualpinball.engine.unity&registry_uri=https://registry.visualpinball.org&color=%2333cf57&logo=unity&style=flat)](https://registry.visualpinball.org/-/web/detail/org.visualpinball.engine.unity.urp)
+
 *Universal Render Pipeline support for the Visual Pinball Engine.*
 
-## Setup
+---
 
 Don't forget to set `ENABLE_HYBRID_RENDERER_V2`, otherwise you won't see anything rendered in play mode.