title: iTunes Connect: Option to change primary language is not editable
body: <p>I have a published app version with a list of localized languages (Danish, English-UK, French, etc) and "Danish" as primary language inside iTunes Connect.</p>
  
  <p>I want to create another version but now with "English-UK" as the default language. But iTunes Connect is not showing me any dropdown for changing the primary language.</p>
  
  <p>How can I do this?</p>