Add XML schema
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index a4db83e..0471499 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -45,7 +45,9 @@
If the output is not quite correct, check for invisible trailing spaces!
-->
-<document>
+<document xmlns="http://maven.apache.org/changes/1.0.0"
+ xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http://maven.apache.org/changes/1.0.0 http://maven.apache.org/xsd/changes-1.0.0.xsd">
<properties>
<title>Apache Commons Math Release Notes</title>
</properties>
