Update to min 9.0.0 in the CI

[miriampolzer]

Trying out if this works. If I understand correctly, CI workflows should be triggered once I create a draft pull request.

[miriampolzer]

looks like the debian CI is still sing 8.20: https://packages.debian.org/sid/coq which fits with https://tracker.debian.org/pkg/coq, 9.0.0. would need to go to experimental.

[miriampolzer]

coqc --version doesn't exist anymore on 9.0.0. I should fx that while I am at it.

[miriampolzer]

New config should pull the coq 9 package from experimental in debian. Let's see...

[miriampolzer]

Nice, thanks! Debian run looks good now, but CI not finished yet. I will check back later.
coqc --version
The Rocq Prover, version 9.1.0
(interesting - on another run, not sure which OS it was I saw coqc not being found with rocq 9.0.0)

[miriampolzer]

docker master: The Rocq Prover, version 9.3+alpha
arch linux: The Rocq Prover, version 9.1.1
alpine edge: The Rocq Prover, version 9.0.0
debian sid: The Rocq Prover, version 9.1.0
windows: The Rocq Prover, version 9.0.0
macos: The Rocq Prover, version 9.0.0
looks good to me. @andres-erbsen I think this is ready, please review.

[andres-erbsen]

This looks good. But maybe let's merge it next time we'd alternatively have to spend time getting 8.20 to build. (I'm guessing the current PRs, as refactored, can go in without that). Merging now would be fine by me as well, but I don't expect it to go stale.