Update Readme with newly added variations

Author: jjohannes

.gitignore

@@ -1,3 +1,4 @@
 .gradle
 .idea
 build
+target

README.md

@@ -12,10 +12,16 @@ The structure though, is good for any kind of project you may build with Gradle
 > [!NOTE]
 > There are adjustments on other branches of this repo that show how the setup can be varied:
 > - 🧩 [**Java Module System**](https://github.com/jjohannes/gradle-project-setup-howto/tree/java_module_system)
+> - 📦 [**Versions in BOM/Platform**](https://github.com/jjohannes/gradle-project-setup-howto/tree/java_bom)
 > - 🦩 [**Kotlin**](https://github.com/jjohannes/gradle-project-setup-howto/tree/kotlin)
 > - 🤖 [**Android**](https://github.com/jjohannes/gradle-project-setup-howto/tree/android)
 > - 🍃 [**Java** and **Spring Boot**](https://github.com/jjohannes/gradle-project-setup-howto/tree/spring_boot)
 
+> [!TIP]
+> For comparison, there are also Maven variants of the setup: 
+> - 🦉 [**Maven**](https://github.com/jjohannes/gradle-project-setup-howto/tree/java_mavenized)
+> - 🧩 [**Maven & Java Module System**](https://github.com/jjohannes/gradle-project-setup-howto/tree/java_module_system_mavenized)
+
 This is following similar patterns as [idiomatic-gradle](https://github.com/jjohannes/idiomatic-gradle)
 but is closer to a _full_ setup that also takes the aspect of continuously changing dependencies into account.