CI container image interference between staging and staging-7.2

[Stefan Hajnoczi]

Hi,
TL;DR Michael: Please check that the staging-7.2 branch has Dan's
commit e28112d00703abd136e2411d23931f4f891c9244 ("gitlab: stable
staging branches publish containers in a separate tag").

I couldn't explain a check-cfi-x86_64 failure
(https://gitlab.com/qemu-project/qemu/-/jobs/5072006964), so I reran
build-cfi-x86_64 to see if it has an effect on its dependencies.

To my surprise the rerun of build-cfi-x86_64 failed:
https://gitlab.com/qemu-project/qemu/-/jobs/5072087783

The first run was successful:
https://gitlab.com/qemu-project/qemu/-/jobs/5071532799

Diffing the output shows that the software versions are different. The
successful run has Python 3.11.5 and meson 1.0.1 while the failed run
has Python 3.10.8 and meson 0.63.3.

I think staging and staging-7.2 pipelines are interfering with each
other. My understanding is that build-cfi-x86_64 uses
registry.gitlab.com/qemu-project/qemu/qemu/fedora:latest and that
should be built from fedora:38. Python 3.10.8 is what Fedora 35 uses.
The staging-7.2 branch's fedora.docker file uses fedora:35.

Stefan