title: Regex for matching XX/YY strings but not XX/YY/ZZ strings
body: <p>I would like to try and match text that is in the form of</p>
  <pre><code>&lt;some digits&gt;/&lt;some digits&gt;
  </code></pre>
  <p>, but NOT</p>
  <pre><code>&lt;some digits&gt;/&lt;some digits&gt;/&lt;some digits&gt;
  </code></pre>
  <p>As an example, if the text is</p>
  <pre><code>01/21
  </code></pre>
  <p>or</p>
  <pre><code>1/21
  </code></pre>
  <p>I would like to match those, but not</p>
  <pre><code>1995/01/01
  </code></pre>
  <p>or</p>
  <pre><code>5/12/92
  </code></pre>
  <p>The background for this is that I am using Duckling to detect dates, and it detects dates like &quot;12/21&quot;, but classifies this as MM/DD, whereas I want it to treat it as YY/MM, so I would like to correct these detections.</p>
  <p>How would I do this?
  Thanks</p>