Update README.MD

Author: QIU2014

README.MD

@@ -8,6 +8,7 @@ A small chinese game written in java
 ![GitHub Actions Workflow Status](https://img.shields.io/github/actions/workflow/status/QIU2014/GoBangGame/ant.yml)
 ![GitHub Issues or Pull Requests](https://img.shields.io/github/issues/QIU2014/gobanggame)
 ![GitHub Repo stars](https://img.shields.io/github/stars/QIU2014/GobangGame?style=flat) <br>
+![GitHub repo size](https://img.shields.io/github/repo-size/QIU2014/GoBangGame)
 ![SourceForge Downloads](https://img.shields.io/sourceforge/dt/GoBangGame?label=SourceForge%20Downloads)
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