add autoVersionSubmodules=true to m-release-p

git-svn-id: https://svn.apache.org/repos/asf/maven/doxia/doxia/trunk@1471163 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index 72cfe07..406b49f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -329,6 +329,7 @@
           <artifactId>maven-release-plugin</artifactId>
           <configuration>
             <tagBase>https://svn.apache.org/repos/asf/maven/doxia/doxia/tags</tagBase>
+            <autoVersionSubmodules>true</autoVersionSubmodules>
           </configuration>
         </plugin>
         <plugin>