[nova] weekly meeting is canceled during the holidays

Hi, As we agreed on the weekly meeting the nova meeting schedule will look like the following during the next weeks: Dec 17 2020 16:00 UTC, #openstack-meeting-3 Dec 24 2020 16:00 UTC, Cancelled Dec 31 2020 16:00 UTC, Cancelled Jan 7 2021 16:00 UTC, #openstack-meeting-3 Cheers, gibi