use maven indexer released version

Signed-off-by: olivier lamy <olamy@apache.org>

pom.xml

@@ -59,8 +59,7 @@
     <aether.version>1.13.1</aether.version>
 
     <maven-model-converter.version>2.1</maven-model-converter.version>
-    <!-- TODO: Before Release 3.0 check, if stable version will be released -->
-    <maven.indexer.version>6.0-SNAPSHOT</maven.indexer.version>
+    <maven.indexer.version>6.0.0</maven.indexer.version>
     <wagon.version>3.0.0</wagon.version>
     <redback.version>3.0.0-SNAPSHOT</redback.version>
     <redback.cache.version>2.2</redback.cache.version>