title: Format labels in an ExtJS 6 bar-chart
body: <p>In <a href="/questions/tagged/extjs4" class="post-tag" title="show questions tagged &#39;extjs4&#39;" rel="tag">extjs4</a> I used the <code>renderer</code> property of a label (assigned to an axis in a bar chart) to format the value. <strong><em>e.g.</em></strong> with something like:</p>
  
  <pre class="lang-js prettyprint-override"><code>axes = [{
      type: 'numeric',
      position: 'left',
      label: {
          renderer: function(v) {
              return String(v) + 'KB';
          }
      }
      ...
  </code></pre>
  
  <p>According to the <a href="https://docs.sencha.com/extjs/6.0/6.0.1-classic/#!/api/Ext.chart.label.Label" rel="nofollow"><code>Ext.chart.label.Label</code> manual</a> this config property has been removed in newer versions.  How can I achieve this in ExtJS Version 6?</p>