Update Maven Central badge in README (#213)

Previous badge was deprecated and not working.

Author: isaacbrodsky

README.md

@@ -5,7 +5,7 @@
 [![tests](https://github.com/uber/h3-java/workflows/tests/badge.svg)](https://github.com/uber/h3-java/actions)
 [![Coverage Status](https://coveralls.io/repos/github/uber/h3-java/badge.svg?branch=master)](https://coveralls.io/github/uber/h3-java?branch=master)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](LICENSE)
-[![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.uber/h3/badge.svg)](https://maven-badges.herokuapp.com/maven-central/com.uber/h3)
+[![Maven Central](https://img.shields.io/maven-central/v/com.uber/h3)](https://central.sonatype.com/artifact/com.uber/h3)
 [![H3 Version](https://img.shields.io/badge/h3-v4.5.0-blue.svg)](https://github.com/uber/h3/releases/tag/v4.5.0)
 
 This library provides Java bindings for the [H3 Core Library](https://github.com/uber/h3). For API reference, please see the [H3 Documentation](https://h3geo.org/).