Bump maven-pmd-plugin from 3.14.0 to 3.15.0

Bumps [maven-pmd-plugin](https://github.com/apache/maven-pmd-plugin) from 3.14.0 to 3.15.0.
- [Release notes](https://github.com/apache/maven-pmd-plugin/releases)
- [Commits](apache/maven-pmd-plugin@maven-pmd-plugin-3.14.0...maven-pmd-plugin-3.15.0)

---
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] <[email protected]>

Author: dependabot[bot]

pom.xml

@@ -29,7 +29,7 @@
         <checkstyle.version>2.11</checkstyle.version>
         <findbugs.version>3.0.5</findbugs.version>
         <javadoc.version>3.3.1</javadoc.version>
-        <pmd.version>3.14.0</pmd.version>
+        <pmd.version>3.15.0</pmd.version>
         <jdepend.version>2.0</jdepend.version>
         <javancss.version>2.0</javancss.version>
         <project.info.version>2.4</project.info.version>