Update README.adoc

Author: Swissbite

README.adoc

@@ -26,7 +26,7 @@ This tutorial is designed for Java developers who have already had their hands o
 
 To start working on this tutorial, we'll need one of the latest versions of IntelliJ IDEA – any version from 2018.1 onwards.You can download the latest free community version https://www.jetbrains.com/idea/download[here].
 
-This project is based on Spring Boot 2.4.0, which requires Kotlin 1.4.10. Make sure version 1.4+ of the Kotlin plugin is installed.To update the Kotlin plugin, use `Tools | Kotlin | Configure Kotlin Plugin Updates`.
+This project is based on Spring Boot 3.1.2 with Kotlin 1.9.0. Make sure version 1.9+ of the Kotlin plugin is installed. To update the Kotlin plugin, use `Tools | Kotlin | Configure Kotlin Plugin Updates`.
 
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