Add third Family and Friends Day

Why is this change being made?

Many summer/winter travel plans have been significantly disrupted in 2020, and many families have children that will soon return to school. This merge request adds a third Family and Friends Day to prioritize wellbeing and make space to celebrate those closest to us.

I'm proposing 2020-08-14, ahead of many schools resuming and the e-group offsite, but welcome feedback on an alternate date.

Author Checklist

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