Add p=1 to weekly cargo update

[clubby789]

Since bumping dependencies tends to be very conflictly.

Blocked on rust-lang/homu#211 (if that takes a while this could just be a followup comment instead).

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[matthiaskrgr]

doesn't that mean we also have to p=1 everything that conflicts with an automatic cargo update because its in the queue for longer and equally conflicty?

[clubby789]

Well my reasoning was that while a regular PR author can just rebase, the bot won't until the next CI run a week later

[matthiaskrgr]

lol, so if there are merge conflicts or something else is broken, we just wait for another week? 😅

imo we should prioritize human-made prs since rebasing these requires a human to spend time, whereas remaking an automated cargo update ps is already automatized and doesn't really require any human intervention?

[Mark-Simulacrum]

The workflow can already be run manually (at least by some people, not sure by who). Could we make it auto-rebase an open PR, say, every hour? It seems to me that the purpose here is similar to dependabot: we want to always have an open PR with the latest set of changes in it, that's approved at some time after it's opened (and shouldn't be changed while approved) but otherwise is continuously kept up to date.

[clubby789]

Sounds reasonable. Maybe we can split this into 2 CI jobs, one to open a PR weekly and another to (hourly) rebase any currently-open PR?

[clubby789]

I'd still like to add rollup=never if the Homu PR lands 🤞🏻