title: Woocommerce hook before order status change
body: <p>I've been searching for a hook that is triggered before the order status is changed or, for that matter, before the order is updated.</p>
  
  <p>I'm trying to enforce a designed workflow. I've been able to change the options the users have to change the order status so they don't choose a 'wrong' status, but I want to check the updates using code too (never trust user input).</p>
  
  <p>There are hooks triggered after the status has changed (woocommerce_order_status[to]) that do not prevent 'illegal' status changes.</p>
  
  <p>Any ideas?</p>