Issue #182: Update pom.xml

Add reference to xml config that tries to download RAT in submodule pge.

rat/pom.xml

diff --git a/rat/pom.xml b/rat/pom.xml
index 61ccb0c..686e471 100644
--- a/rat/pom.xml
+++ b/rat/pom.xml
@@ -43,6 +43,7 @@
     <dependency>
       <groupId>org.apache.rat</groupId>
       <artifactId>apache-rat</artifactId>
+      <!-- do not forget to update https://github.com/apache/drat/blob/master/pge/src/main/resources/config/PgeConfig_Rat.xml in case of RAT-updates as well -->
       <version>0.13</version>
     </dependency>  
   </dependencies>