Add new project logo.

git-svn-id: https://svn.apache.org/repos/asf/xml/commons/trunk@226104 13f79535-47bb-0310-9956-ffa450edef68

src/documentation/skinconf.xml

@@ -69,7 +69,7 @@ be used to configure the chosen Forrest skin.
        skin: forrest-site renders it at the top -->
   <project-name>xml-commons</project-name>
   <project-url>http://xml.apache.org/xml-commons/</project-url>
-  <project-logo>images/project-logo.png</project-logo>
+  <project-logo>images/project-logo.gif</project-logo>
 
   <!-- optional group logo
        skin: forrest-site renders it at the top-left corner -->