Upgrade ivy.api.reference version to 2.5.0

Contributed-by: Gintautas Grigelionis
Pull request: #90

Author: jaikiran

build.properties

@@ -47,7 +47,7 @@ rat.report.dir=${reports.dir}/rat
 ivy.minimum.javaversion=1.8
 debug.mode=on
 ivy.install.version=1.4.1
-ivy.api.reference=2.4.0
+ivy.api.reference=2.5.0
 
 #status=integration