Update to latest RAT release 0.13
diff --git a/rat/pom.xml b/rat/pom.xml
index 5313d87..61ccb0c 100644
--- a/rat/pom.xml
+++ b/rat/pom.xml
@@ -43,7 +43,7 @@
     <dependency>
       <groupId>org.apache.rat</groupId>
       <artifactId>apache-rat</artifactId>
-      <version>0.12</version>
+      <version>0.13</version>
     </dependency>  
   </dependencies>