Bug 1562628: Run the periodic file update cron job on ESR68; r=bhearsum

It turns out there are two places that need to be updated, remove one
of them, and update the other.

Differential Revision: https://phabricator.services.mozilla.com/D36975

--HG--
extra : moz-landing-system : lando

.cron.yml

@@ -172,24 +172,10 @@ jobs:
           - mozilla-beta
           - mozilla-release
           - mozilla-esr60
+          - mozilla-esr68
       when:
-          by-project:
-              # No default branch
-              mozilla-central:
-                  - {weekday: 'Monday', hour: 10, minute: 0}
-                  - {weekday: 'Thursday', hour: 10, minute: 0}
-              mozilla-beta:
-                  - {weekday: 'Monday', hour: 10, minute: 0}
-                  - {weekday: 'Thursday', hour: 10, minute: 0}
-              mozilla-release:
-                  - {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}
-              mozilla-esr68:
-                  - {weekday: 'Monday', hour: 10, minute: 0}
-                  - {weekday: 'Thursday', hour: 10, minute: 0}
+          - {weekday: 'Monday', hour: 10, minute: 0}
+          - {weekday: 'Thursday', hour: 10, minute: 0}
 
     - name: pipfile-update
       job: