Update README.md

Author: KTC-YoheiMiyashita

README.md

@@ -2,7 +2,7 @@ Spring Batch3 Starter - Accelerate Your Spring Boot 3 Batch Development🚀
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 [![Github](https://img.shields.io/github/stars/KTC-YoheiMiyashita/SpringBoot3BatchStarter?logo=github&style=flat)](https://github.com/KTC-YoheiMiyashita/SpringBoot3BatchStarter)
 [![GitHub Actions Build Status](https://github.com/KTC-YoheiMiyashita/SpringBoot3BatchStarter/actions/workflows/Java%20CI/badge.svg)](https://github.com/KTC-YoheiMiyashita/SpringBoot3BatchStarter/actions?query=workflow%3A%22Java+CI%22)
-![Java 11+](https://img.shields.io/badge/Java-11%2B-blue)
+![Java 21](https://img.shields.io/badge/Java-21%2B-blue)
 [![License: MIT](https://img.shields.io/badge/License-MIT-green.svg)](https://opensource.org/licenses/MIT)
 
 # SpringBoot3BatchStarter