CI: replace centos:7 container by redhat/ubi9:latest

[andreasabel]

Github disabled workflow ci.yml because its job centos7 perpetually failed (Centos EOL).
This replaces the centos:7 image by redhat/ubi9:latest.

SQUASH this PR upon merge.

[Bodigrim]

CentOS 9 is not as much different from other distros as CentOS 7 used to be, so I’m personally inclined to drop this CI job if it’s nontrivial to set up.

[andreasabel]

Somewhere it has been said that redhat/ubi9 would be a replacement for centos. It seems to work with minimal changes (dropping the obsolote ncurses-compat-libs).

ci.yml succeeds again.

[Bodigrim]

Thanks!

[Bodigrim]

Arrrgh, I forgot to squash, will push --force in a moment.

[Bodigrim]

Apparently even my access level is not enough to push --force, I think a few repos were branch-protected by GitHub support a few years ago. Let's leave it as a monument to my inability to read.

[andreasabel]

Ok, no worries. Been there, done that. :-D

Thanks!

[andreasabel]

I wish github would have a special label like "squash me" that one would have to remove first if one wanted to merge other than squash... In the Agda repo, I created the "pr: squash me" label, but it is easy to overlook, does not have the magic I want it to have...