Add back presubmit (oops), and add cron. (#272)
Add back presubmit (oops), and add cron. (#272)

* Add back presubmit (oops), and add cron.

* Apparently I broke it too :(

* Comment wait due to chaos

* Add slack notifications on post-submit failures
knative-sandbox/net-contour,knative-sandbox/net-contour