UTF-8 encoding is not added to xml metadata tag by ear plugin

I am generating the application.xml using the ear plugin. The generated xml does not include UTF-8 encoding.
Please help.

Expected :

<?xml version="1.0" encoding="UTF-8"?>

Actual :

<?xml version="1.0"?>

build file

ear {
  archiveName = 'AdminGui.ear'	
  deploymentDescriptor {
      displayName = 'AdminGui'	
      webModule(warName, "/admin-web")
   }
}