switch maven central badge to shields.io to avoid out-of-sync issues with maven index

Author: stefanseifert

README.md

@@ -1,7 +1,7 @@
 <img src="https://wcm.io/images/favicon-16@2x.png"/> Eclipse Maven Plugin
 ======
 [![Build](https://github.com/wcm-io-devops/eclipse-maven-plugin/workflows/Build/badge.svg?branch=develop)](https://github.com/wcm-io-devops/eclipse-maven-plugin/actions?query=workflow%3ABuild+branch%3Adevelop)
-[![Maven Central](https://maven-badges.herokuapp.com/maven-central/io.wcm.devops.maven.plugins/eclipse-maven-plugin/badge.svg)](https://maven-badges.herokuapp.com/maven-central/io.wcm.devops.maven.plugins/eclipse-maven-plugin)
+[![Maven Central](https://img.shields.io/maven-central/v/io.wcm.devops.maven.plugins/eclipse-maven-plugin)](https://repo1.maven.org/maven2/io/wcm/devops/maven/plugins/eclipse-maven-plugin)
 
 The Eclipse Plugin is used to generate Eclipse IDE files (.project, .classpath and the .settings folder) from a POM.