Update cron workflow name

[jrdnbradford]

It looks like 845f8e5 changed cron.yaml to run weekly instead of daily, but the name of the workflow was left as daily. This just updates the name.

(Or perhaps the name should be something like scheduled-schema-update?)

[sirosen]

Thanks for this; good catch!

Let's leave it with "weekly" for now. The idea I had when I named the prior one "daily" was that it would be the workflow for potentially multiple daily jobs. So, following that reasoning, this is a workflow for any weekly jobs. (I'm not super attached to this scheme, but I'd rather not change it unless there's a clear reason to do so.)

I'll look at that build failure after merging this. I'm guessing that py3.8 support is uneven across upstream libraries, and it leads to some weird situation.

[jrdnbradford]

Awesome, see my link in my accidental PR #474 re the mindeps issue.