compiler warning fixes
diff --git a/pom.xml b/pom.xml
index cc31002..206b574 100644
--- a/pom.xml
+++ b/pom.xml
@@ -75,7 +75,7 @@
         <plugin>
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-site-plugin</artifactId>
-            <version>3.0</version>
+            <version>3.1</version>
         </plugin>
         <plugin>
             <groupId>org.apache.maven.plugins</groupId>