Update to Jython 2.5.3

Fixes gh-8638

gradle/dependency-management.gradle

@@ -16,7 +16,7 @@ dependencyManagement {
 		dependency 'org.powermock:powermock-module-junit4-common:2.0.7'
 		dependency 'org.powermock:powermock-module-junit4:2.0.7'
 		dependency 'org.powermock:powermock-reflect:2.0.7'
-		dependency 'org.python:jython:2.5.0'
+		dependency 'org.python:jython:2.5.3'
 		dependency 'org.spockframework:spock-core:1.0-groovy-2.4'
 		dependency 'org.spockframework:spock-spring:1.0-groovy-2.4'
 	}