Fix: not enough arguments to call TransformExcC14n (#428)

Author: lakkiy

schema.go

@@ -747,7 +747,7 @@ func (a *Assertion) Element() *etree.Element {
 	for _, attributeStatement := range a.AttributeStatements {
 		el.AddChild(attributeStatement.Element())
 	}
-	err := etreeutils.TransformExcC14n(el, canonicalizerPrefixList)
+	err := etreeutils.TransformExcC14n(el, canonicalizerPrefixList, false)
 	if err != nil {
 		panic(err)
 	}