Start building against Fedora 40

[FlyinPancake]

Describe the bug

Fedora 40 Beta is now available https://www.redhat.com/en/blog/fedora-40-beta-now-available

Fedora 40 now ships KDE 6 which supports HDR for gaming, so it is crucial to start testing as soon as possible, since there are some breaking changes introduced.

ublue/main now builds a fedora 40 image https://github.com/ublue-os/main/pkgs/container/kinoite-main/198110346?tag=40

What did you expect to happen?

I'd like to see 40-testing images built against ublue/main.

Output of rpm-ostree status

No response

Hardware

No response

Extra information or context

No response

[FlyinPancake]

Upstream tracks the issue over here

ublue-os/main#529

[zqpvr]

I would like this.

[bsherman]

Done.