fixes maven central badge

Author: delthas

README.md

@@ -1,6 +1,6 @@
 ![](https://img.shields.io/travis/Delthas/JavaMP3.svg) 
 ![](https://img.shields.io/github/license/Delthas/JavaMP3.svg)
-![](https://img.shields.io/maven-central/v/fr.delthas/JavaMP3.svg)
+![](https://img.shields.io/maven-central/v/fr.delthas/javamp3.svg)
 # JavaMP3
 
 **Currently supports MPEG-1 Layer I/II/III (that is, most MP1, MP2, and MP3 files)**