I think this is already documented in the release workflow, but as I'm not centrally involved in releases, I don't follow that doc myself.
The PR above shows what we're doing each release; the cron job runs because there is dated content in the website and if the website isn't rebuilt every 6 hours or so, it will quickly become stale and out-of-date.
(eg. http://fluxcd.io/community/#meetings)
We can merge #2165 to get the website updating again for now, but I'm creating this issue because it seems like a trivial thing to automate, and I don't want to lose track of that we need to do that before the next Minor release (in Q3 or whenever it is scheduled, a long while from now...)