title: Java DateTimeFormatter for time zone with an optional colon separator?
body: <p>I'm trying to build a DateTimeFormatter that can accepts offset with colon or offset without colon.</p>
  
  <p>Is there a way to pass this test :</p>
  
  <pre><code>DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss[X]");
  dateTimeFormatter.parse("2015-01-28T10:21:44+0100"); // OK
  dateTimeFormatter.parse("2015-01-28T10:21:44+01:00"); // KO
  </code></pre>