Update to PMD 6.9.0

Refs #48

Author: adangel

ReleaseNotes.md

@@ -11,7 +11,7 @@ Eclipse Update Site:
 
 ### New and noteworthy
 
-*   Updated PMD to 6.7.0
+*   Updated PMD to 6.9.0
 *   Eclipse SimRel 2018-09 is supported.
     To do this, the plugin doesn't expose log4j for other plugins anymore
     (the package `org.apache.log4j` is not exported anymore). In case you used this in a fragment,

pom.xml

@@ -16,7 +16,7 @@
   <properties>
     <tycho.version>1.1.0</tycho.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <pmd.version>6.7.0</pmd.version>
+    <pmd.version>6.9.0</pmd.version>
     <maven-antrun-plugin.version>1.8</maven-antrun-plugin.version>
   </properties>