fix(releasing): add missing maven-site-plugin

Author: KaiSchwarz-cnic

pom.xml

@@ -158,6 +158,11 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+    <groupId>org.apache.maven.plugins</groupId>
+      <artifactId>maven-site-plugin</artifactId>
+      <version>3.7.1</version>
+    </plugin>
     </plugins>
   </build>
   <dependencies>