JSIEVE-111 Upgrade apache-rat-plugin 0.13
diff --git a/pom.xml b/pom.xml
index a96ae1c..023fab1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -221,6 +221,7 @@
             <plugin>
                 <groupId>org.apache.rat</groupId>
                 <artifactId>apache-rat-plugin</artifactId>
+                <version>0.13</version>
                 <configuration>
                     <excludes>
                         <exclude>**/*help.txt</exclude>