Bump org.apache.maven.plugins:maven-site-plugin in /java/case2geo

Bumps [org.apache.maven.plugins:maven-site-plugin](https://github.com/apache/maven-site-plugin) from 3.20.0 to 3.21.0.
- [Release notes](https://github.com/apache/maven-site-plugin/releases)
- [Commits](apache/maven-site-plugin@maven-site-plugin-3.20.0...maven-site-plugin-3.21.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

java/case2geo/pom.xml

@@ -96,7 +96,7 @@
         https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
         <plugin>
           <artifactId>maven-site-plugin</artifactId>
-          <version>3.20.0</version>
+          <version>3.21.0</version>
         </plugin>
         <plugin>
           <artifactId>maven-project-info-reports-plugin</artifactId>