doc: Add maven badge for README.md

Jacksunwei · copybara-github · commit e25696259d4b · 2025-08-11T10:09:05.000-07:00
PiperOrigin-RevId: 793694841
diff --git a/README.md b/README.md
@@ -1,6 +1,7 @@
 # Agent Development Kit (ADK) for Java
 
 [![License](https://img.shields.io/badge/License-Apache_2.0-blue.svg)](LICENSE)
+[![Maven Central](https://img.shields.io/maven-central/v/com.google.adk/google-adk)](https://search.maven.org/artifact/com.google.adk/google-adk)
 [![r/agentdevelopmentkit](https://img.shields.io/badge/Reddit-r%2Fagentdevelopmentkit-FF4500?style=flat&logo=reddit&logoColor=white)](https://www.reddit.com/r/agentdevelopmentkit/)
 
 <html>
