CI: Update images, versions

[eschnett]

No description provided.

[eschnett]

Turns out the h5p_get_external problem wasn't a "32-bit Windows bug", it was a "32-bit bug". The Julia definition of off_t (a POSIX type) was wrong. I'm fixing this as a drive-by correction in this PR to make all the CI tests work.

[eschnett]

This is ready for review and/or merging.

The time-out is a slow multi-threaded test on 64-bit Windows for Julia 1.9 – the same test succeeds for 32-bit Windows and for all other Julia versions.

[mkitti]

This seems good. Should we tighten up the compat though?

[eschnett]

Do you want to stop testing with Julia 1.9, or declare that Julia 1.9 cannot be used?

I think the tests still run reasonably fast and there is no reason to test fewer Julia versions. The slow tests are the Windows multi-threaded lock tests. I don't know why they are slow or timing out, maybe they are running out of memory and testing with a smaller array might help?

[mkitti]

Do you want to stop testing with Julia 1.9, or declare that Julia 1.9 cannot be used?

To me these are not distinct steps. If we stop testing on 1.9, we should not declare compat with 1.9 because we do not know if that is true or not.

I also do not think we need to support unsupported versions of Julia. If we have a reason to move the minimum compat to Julia 1.10 then we should without hesitation.

[eschnett]

Okay. I think there is no reason to move to 1.10 at the moment, but also no reason to stick with 1.9...