Bug 1499590 - Add periodic-file-updates task to .cron.yml. r=dustin
Added configuration for periodic-file-updates task to comm's .cron.yml.
This cron task mirrors one found in mozilla- repositories, and was part of
comm-'s buildbot configuration that needed to be moved to Taskcluster.
Differential Revision:
https://phabricator.services.mozilla.com/D9859
{
"phabricator.uri" : "https://phabricator.services.mozilla.com/",
"repository.callsign": "COMMCENTRAL",
"history.immutable": false
}