title: "month out of range" when parsing date without separators
body: <p>Any ideas how to get golang to properly parse a date string such as <code>31916</code>
  I keep getting a <strong>month out of range</strong> error.</p>
  
  <pre><code>date, err := time.Parse("1206", "31916")
  fmt.Println(date, err)
  </code></pre>
  
  <p>Of course I want to treat the month as 3 and not 31 like it's doing, but I'm not sure how to force it to stop at 3 for the month outside of adding separators to the format.</p>