Bump maven-pmd-plugin from 3.19.0 to 3.20.0

Bumps [maven-pmd-plugin](https://github.com/apache/maven-pmd-plugin) from 3.19.0 to 3.20.0.
- [Release notes](https://github.com/apache/maven-pmd-plugin/releases)
- [Commits](apache/maven-pmd-plugin@maven-pmd-plugin-3.19.0...maven-pmd-plugin-3.20.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-pmd-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -26,7 +26,7 @@
 
         <checkstyle.version>3.2.0</checkstyle.version>
         <javadoc.version>3.4.1</javadoc.version>
-        <pmd.version>3.19.0</pmd.version>
+        <pmd.version>3.20.0</pmd.version>
         <project.info.version>3.1.1</project.info.version>
         <jxr.version>3.3.0</jxr.version>
         <taglist.version>3.0.0</taglist.version>