End regularly scheduled Zuul meetings

The Zuul team has determined[1] that due to the timezone spread, weekly
meetings are impractical and would like to attempt conducting our
work through email and ad-hoc meetings.

Therefore, remove the Zuul meeting from the schedule.

[1] http://lists.zuul-ci.org/pipermail/zuul-discuss/2018-April/000107.html

Change-Id: Ic847cea29a787d7528b2e8d37af590c24a19965a

meetings/zuul-meeting.yaml

@@ -1,12 +0,0 @@
-project:  Zuul Meeting
-meeting_id: zuul
-agenda_url: https://wiki.openstack.org/wiki/Meetings/Zuul
-schedule:
-  - time:       '2200'
-    day:        Monday
-    irc:        openstack-meeting-alt
-    frequency:  weekly
-    start_date: 20161114
-chair:  James E. Blair (jeblair)
-description:  >
-  A weekly meeting to discuss Zuul development.