title: Format labels on AG-Grid charts
body: <p>How can I format the labels that appear on AG-Grid chart's axis?  I have a lot of time-series data so I expect users frequently to produce charts where the horizontal axis is a date. Unfortunately, this produces unreadable chart labels because the dates are not formatted (see attached image) - The labels look like "Thu Jan 09 2020 00:00:00 GMT+0000 (Greenwich Mean Time)" when all I would like is simply "2020-01-09". My The dates in the grid look fine thanks to a valueFormatter for dates.  </p>
  
  <p>It is also very common for users to produce pivot tables using the date. This produces similarly terrible results for the labels, but I've found I can use "processSecondaryColGroupDef" to format dates that appear in the column headers. Is there a similar way to do this for charts?</p>
  
  <p>Thankyou,
  Troy.<a href="https://i.stack.imgur.com/QysDV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QysDV.png" alt="enter image description here"></a></p>