CI: Use -qq for apt in deploy

Sigh. One last thing.

Anyway as a side note, it turns out that the reason deploys aren't working is because this looks like the only place where MR pipelines are really special.

We want to have deploy jobs in the main repo only, so we can make sure we don't leak the secret SSH key. I'd used the Mesa jobs as a reference, as well as tested on my own fork, both of which worked. The reason this one isn't working is because every Mesa MR has its last MR pipeline created by @marge-bot (who is a developer in Mesa), and my downstream tests had the MR pipeline created by me (being an owner of my own repo).

What happens here is that GitLab doesn't create a pipeline for the post-merge push to main, because the pipeline is triggered by me (as a non-developer of this repo, just using my admin rights to merge anyway). This means that I have to manually create a pipeline for main to go force the deploy.

I'm not sure if this means that every MR submitted by a non-developer will have the same issue, or if it's just the special case of people who aren't developers on the repo but can still push merge because they're in admin mode. Let's find out, I guess.