pull-request-2024-04-25

Thomas Huth

@thuth

17523a38 · target/s390x: Remove KVM stubs in cpu_models.h · Apr 25, 2024

* Update OpenBSD CI image to 7.5
* Update/remove Ubuntu 20.04 CI jobs
* Update (most) CentOS 8 CI jobs to CentOS 9
* Some clean-ups and improvements to travis.yml
* Minor test fixes
* s390x header clean-ups
* Doc updates