chore(deps): update dependency org.apache.maven.plugins:maven-site-plugin to v3.21.0 (#118)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

pom.xml

@@ -41,7 +41,7 @@
         <maven-jar-plugin-version>3.2.2</maven-jar-plugin-version>
         <maven-javadoc-plugin-version>3.4.1</maven-javadoc-plugin-version>
         <maven-compiler-plugin-version>3.10.1</maven-compiler-plugin-version>
-        <maven-site-plugin-version>3.12.1</maven-site-plugin-version>
+        <maven-site-plugin-version>3.21.0</maven-site-plugin-version>
         <maven-checkstyle-plugin-version>3.2.0</maven-checkstyle-plugin-version>
         <maven-reports-plugin-version>3.9.0</maven-reports-plugin-version>
         <maven-failsafe-plugin-version>3.0.0-M7</maven-failsafe-plugin-version>