title: Magento 2 CMS Page 'Layout Update XML' option add xml code to get custom meta tag
body: <p>I know how to add custom meta tag in a <strong>Magento 1</strong> CMS page using 'Layout Update XML' option.</p>
  
  <pre><code>&lt;reference name="head"&gt;
      &lt;block type="core/text" name="custommeta"&gt;
          &lt;action method="setText"&gt;
              &lt;text&gt;
                  &lt;![CDATA[&lt;meta data-customid="customid_meta_1" /&gt;]]&gt;
              &lt;/text&gt;
          &lt;/action&gt;
      &lt;/block&gt;
  &lt;/reference&gt;
  </code></pre>
  
  <p>How I can add meta tag in the same way for a specific CMS page in <strong>Magento 2</strong> using option 'Layout Update XML'</p>
  
  <pre><code>&lt;meta data-customid="customid_meta_1" /&gt;
  </code></pre>