Fix of the link in the Maven icon

The maven icon has a search command inside but that seems
to be no longer working so now it's a direct link to the artifact.

README.md

@@ -59,7 +59,7 @@ write the different impulse responses of the filters to text files.
 
 ## Maven central
 
-At [![Maven Central](https://img.shields.io/maven-central/v/uk.me.berndporr/iirj.svg?label=Maven%20Central)](https://search.maven.org/search?q=g:%22uk.me.berndporr%22%20AND%20a:%22iirj%22)
+At [![Maven Central](https://img.shields.io/maven-central/v/uk.me.berndporr/iirj.svg?label=Maven%20Central)](https://central.sonatype.com/artifact/uk.me.berndporr/iirj)
 click on the iirj version number and then choose the appropriate installation option, for
 example for Android studio.