Update README.md

Add deprecation message and update badges.

Author: clementetb

README.md

@@ -1,10 +1,18 @@
+> [!WARNING]
+> We announced the deprecation of Atlas Device Sync + Realm SDKs in September 2024. For more information please see:
+> - [SDK Deprecation](https://www.mongodb.com/docs/atlas/device-sdks/deprecation/)
+> - [Device Sync Deprecation](https://www.mongodb.com/docs/atlas/app-services/sync/device-sync-deprecation/)
+>
+> For a version of Realm Kotlin without sync features, install version `3.0.0+` or see the `community` git branch.
+
+
 <picture>
     <source srcset="./images/logo-dark.svg" media="(prefers-color-scheme: dark)" alt="realm by MongoDB">
     <img src="./images/logo.svg" alt="realm by MongoDB">
 </picture>
 
-[![Gradle Plugin Portal](https://img.shields.io/maven-metadata/v/https/plugins.gradle.org/m2/io/realm/kotlin/io.realm.kotlin.gradle.plugin/maven-metadata.xml.svg?colorB=ff6b00&label=Gradle%20Plugin%20Portal)](https://plugins.gradle.org/plugin/io.realm.kotlin)
-[![Maven Central](https://img.shields.io/maven-central/v/io.realm.kotlin/gradle-plugin?colorB=4dc427&label=Maven%20Central)](https://search.maven.org/artifact/io.realm.kotlin/gradle-plugin)
+[![Gradle Plugin Portal](https://img.shields.io/maven-metadata/v/https/plugins.gradle.org/m2/io/realm/kotlin/io.realm.kotlin.gradle.plugin/maven-metadata.xml.svg?colorB=ff6b00&label=Gradle%20Plugin%20Portal&versionPrefix=2)](https://plugins.gradle.org/plugin/io.realm.kotlin)
+[![Maven Central](https://img.shields.io/maven-central/v/io.realm.kotlin/gradle-plugin/2.3.0?colorB=4dc427&label=Maven%20Central)](https://search.maven.org/artifact/io.realm.kotlin/gradle-plugin)
 [![Kotlin](https://img.shields.io/badge/kotlin-2.0.20-blue.svg?logo=kotlin)](http://kotlinlang.org)
 [![License](https://img.shields.io/badge/License-Apache-blue.svg)](https://github.com/realm/realm-kotlin/blob/master/LICENSE)