Bug 1464816 Run periodic file updates on mozilla-esr60 r=ryanvm

Summary:
I've copied the m-c schedule, as the task sometimes
fails with timeouts. This does add to the releaseduty workload,
until automatic landing is operational.

Reviewers: RyanVM

Reviewed By: RyanVM

Bug #: 1464816

Differential Revision: https://phabricator.services.mozilla.com/D1438

--HG--
extra : rebase_source : 5612fe436d2f44f4d06f21436051256e4052cc43

.cron.yml

@@ -115,3 +115,6 @@ jobs:
               mozilla-central:
                   - {weekday: 'Monday', hour: 10, minute: 0}
                   - {weekday: 'Thursday', hour: 10, minute: 0}
+              mozilla-esr60:
+                  - {weekday: 'Monday', hour: 10, minute: 0}
+                  - {weekday: 'Thursday', hour: 10, minute: 0}