[PNG] Cancel meeting

Hello everyone,

Sorry for the late notice. I've been busy and lost track of the date.
As you know, I normally don't like cancelling 2 meetings in a row. But
there has been no movement since last time, including some work I was
hoping to wrap up.

If we held the meeting, I imagine it would be a 3-minute "So, any updates?
Nope. Okay, have a good one." I think we're better off cancelling this
meeting.

Things on our todo list:
- Resolve merge conflicts in GitHub pull request 387
<https://github.com/w3c/PNG-spec/pull/387>
- Review the semi-new GitHub issues to make sure they aren't blockers for
Third Edition
- Update the Changes section of the spec
- Create a call for consensus once all those are ready to publish a new CR


Sorry again about the late notice. Hope you can make use of the time.