Travis CI change history: Backlog of Jobs on .ORG

Travis CI reported a major backlog of queued MacOS build jobs on .ORG starting at 2020-04-28 22:07 UTC, delaying build processing. A fix was implemented by 2020-04-28 22:25 UTC; the incident was resolved at 2020-04-28 22:57 UTC after 49 min.