Use newer version of pmd
diff --git a/buildtools/pom.xml b/buildtools/pom.xml
index 7bc0da2..4ab55f9 100644
--- a/buildtools/pom.xml
+++ b/buildtools/pom.xml
@@ -75,7 +75,7 @@
         <dependency>
             <groupId>net.sourceforge.pmd</groupId>
             <artifactId>pmd-java</artifactId>
-            <version>5.4.1</version>
+            <version>6.6.0</version>
             <scope>provided</scope>
         </dependency>
     </dependencies>