Bump maven-site-plugin from 3.9.0 to 3.9.1

Bumps [maven-site-plugin](https://github.com/apache/maven-site-plugin) from 3.9.0 to 3.9.1.
- [Release notes](https://github.com/apache/maven-site-plugin/releases)
- [Commits](apache/maven-site-plugin@maven-site-plugin-3.9.0...maven-site-plugin-3.9.1)

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

pom.xml

@@ -227,7 +227,7 @@
                 </plugin>
                 <plugin>
                     <artifactId>maven-site-plugin</artifactId>
-                    <version>3.9.0</version>
+                    <version>3.9.1</version>
                 </plugin>
                 <plugin>
                     <artifactId>maven-scm-publish-plugin</artifactId>