Add info on how to configure JCenter with Maven

Change-Id: I95a30ded41d84b6564d1af321a27ab1d2effb962

Author: pvdissel

README.md

@@ -16,6 +16,8 @@ To get the bol.com OpenAPI client binaries, add the JCenter repository (https://
       <version>4.0.1</version>
   </dependency>
   ```
+
+  See https://github.com/bintray/bintray-examples/blob/master/maven-example/settings.xml on how the add jcenter to your Maven `settings.xml`, or to your `pom.xml`
 
 - Gradle