Bump org.codehaus.mojo:versions-maven-plugin from 2.18.0 to 2.21.0

Bumps [org.codehaus.mojo:versions-maven-plugin](https://github.com/mojohaus/versions) from 2.18.0 to 2.21.0.
- [Release notes](https://github.com/mojohaus/versions/releases)
- [Changelog](https://github.com/mojohaus/versions/blob/master/ReleaseNotes.md)
- [Commits](mojohaus/versions@2.18.0...2.21.0)

---
updated-dependencies:
- dependency-name: org.codehaus.mojo:versions-maven-plugin
  dependency-version: 2.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

pom.xml

@@ -204,7 +204,7 @@
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>versions-maven-plugin</artifactId>
-                <version>2.18.0</version>
+                <version>2.21.0</version>
             </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>