Updated to PMD 6.21.0

Author: adangel

ReleaseNotes.md

@@ -13,6 +13,8 @@ This is a bugfix release.
 
 ### New and noteworthy
 
+*   Updated to PMD 6.21.0
+
 ### Fixed Issues
 
 ### API Changes

pom.xml

@@ -20,7 +20,7 @@
 
     <tycho.version>1.6.0</tycho.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <pmd.version>6.20.0</pmd.version>
+    <pmd.version>6.21.0</pmd.version>
     <maven-antrun-plugin.version>1.8</maven-antrun-plugin.version>
     <pmd.build-tools.version>3</pmd.build-tools.version>
     <checkstyle.version>3.0.0</checkstyle.version>