Bump CMake minimum version to 3.28

[alexreinking]

This is in line with our policy to track the version included in the latest Ubuntu LTS. Version 24.04 LTS now includes CMake 3.28.

Merge after #8362

[alexreinking]

mac-arm-worker-1 hung on Metal again. Machine could need a reboot.

[mcourteaux]

This is annoying... Why bump it if it works?

[mcourteaux]

FYI: LTS releases of Ubuntu are supposed to be supported for 5 years, not 4. So there is a one-year overlap between two successive LTS releases. Now, I'm supposedly on a supported system by Ubuntu LTS guidelines, but Halide disrespects the LTS lifecycle.

[alexreinking]

@mcourteaux - because it enables some significant build improvements that have started being realized over the subsequent PRs.

Also, pip install --user cmake works... everywhere? Upgrading is not an issue except in seriously broken environments.

[alexreinking]

Now, I'm supposedly on a supported system by Ubuntu LTS guidelines, but Halide disrespects the LTS lifecycle.

Also, if you prefer systemwide installations, you can stay on your LTS and use either snap install cmake to get the latest or use Kitware's APT repo if you prefer APT.

[mcourteaux]

Thanks for the tips. I have no problem installing from source, it's just an annoying step. I should reinstall my system and switch from Ubuntu to Fedora either way...