Add maven central badge in readme file

Author: eddumelendez

README.md

@@ -1,5 +1,7 @@
 # Testcontainers
 
+[![Maven Central](https://maven-badges.herokuapp.com/maven-central/org.testcontainers/testcontainers/badge.svg)](https://maven-badges.herokuapp.com/maven-central/org.testcontainers/testcontainers)
+
 [![Open in GitHub Codespaces](https://github.com/codespaces/badge.svg)](https://github.com/codespaces/new?hide_repo_select=true&ref=main&repo=33816473&machine=standardLinux32gb&devcontainer_path=.devcontainer%2Fdevcontainer.json&location=EastUs)
 
 [![Revved up by Gradle Enterprise](https://img.shields.io/badge/Revved%20up%20by-Gradle%20Enterprise-06A0CE?logo=Gradle&labelColor=02303A)](https://ge.testcontainers.org/scans)