Pick up pmd version from parent POM

Author: garydgregory

pom.xml

@@ -173,7 +173,6 @@
     <checkstyle.suppress.file>${basedir}/src/site/resources/checkstyle/checkstyle-suppressions.xml</checkstyle.suppress.file>
     <checkstyle.resourceExcludes>LICENSE.txt, NOTICE.txt, **/maven-archiver/pom.properties</checkstyle.resourceExcludes>
 
-    <commons.pmd-impl.version>6.52.0</commons.pmd-impl.version>
     <commons.spotbugs.version>4.7.3.0</commons.spotbugs.version>
     <commons.spotbugs.impl.version>4.7.3</commons.spotbugs.impl.version>
     <japicmp.skip>false</japicmp.skip>