build(deps): bump org.apache.maven.plugins:maven-site-plugin (package-url#192)

Bumps [org.apache.maven.plugins:maven-site-plugin](https://github.com/apache/maven-site-plugin) from 3.3 to 3.21.0.
- [Release notes](https://github.com/apache/maven-site-plugin/releases)
- [Commits](apache/maven-site-plugin@maven-site-plugin-3.3...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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

pom.xml

@@ -65,7 +65,7 @@
         <maven.javadoc.plugin.version>3.6.3</maven.javadoc.plugin.version>
         <maven.release.plugin.version>3.0.1</maven.release.plugin.version>
         <maven.resources.plugin.version>2.6</maven.resources.plugin.version>
-        <maven.site.plugin.version>3.3</maven.site.plugin.version>
+        <maven.site.plugin.version>3.21.0</maven.site.plugin.version>
         <maven.source.plugin.version>3.3.0</maven.source.plugin.version>
         <maven.surefire.plugin.version>3.5.2</maven.surefire.plugin.version>
         <!-- Maven build plugins for quality checks -->