Expected Behavior

Meter information should be read out for a screenreader user.

Actual Behavior

Currently, Voiceover doesn't have access to read chart text information; just read out as "image" with no content information.

URL, screen shot, or Codepen exhibiting the issue

This issue can be seen in any of the Meter storybook stories
https://storybook.grommet.io/?path=/story/visualizations-meter-bar--bar

Steps to Reproduce

Your Environment

• Grommet version:
• Browser Name and version:
• Operating System and version (desktop or mobile):