title: Select2 v3 > v4 - programmatically set values issue
body: <p>I'm trying to update my JS code to suit v4 (which is used by ACF).</p>
  
  <p>This worked with v3 (where defCountry is a variable set earlier):</p>
  
  <pre><code>$('#s2id_acf-field_554f18ecbf60c-input').select2("data", {id: defCountry, text: defCountry});
  </code></pre>
  
  <p>But it doesn't work with v4. I have tried these but to no avail:</p>
  
  <pre><code>$('#s2id_acf-field_554f18ecbf60c-input').val( defCountry ); 
  $('#s2id_acf-field_554f18ecbf60c-input').val( {id: defCountry, text: defCountry} );
  $('#s2id_acf-field_554f18ecbf60c').val( defCountry ); 
  $('#s2id_acf-field_554f18ecbf60c').val( {id: defCountry, text: defCountry} ); 
  </code></pre>
  
  <p>(Both with and without the trigger option.)</p>