Add badge to README

README.md

@@ -1,5 +1,7 @@
 # PlantUML GitHub Action
 
+[![GitHub release](https://img.shields.io/github/v/release/uclahs-cds/tool-PlantUML-action)](https://github.com/uclahs-cds/tool-PlantUML-action/actions/workflows/prepare-release.yaml)
+
 This repository is a GitHub Action that generates UML diagrams (as SVGs) from PlantUML files.
 
 ## How to use this action in your repository
@@ -164,4 +166,4 @@ Copyright (C) 2021 University of California Los Angeles ("Boutros Lab") All righ
 
 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
 
-This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.