CompatHelper: bump compat for Adapt to 4, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the Adapt package from 3.4.0 to 3.4.0, 4.
This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.

Edit: closes #775

[oxinabox]

why did CI not run?

[oxinabox]

ok here we go

[oxinabox]

According to CI this actually failed to be resolvable.
I think we need to concurrently relax bounds on Adapt, StaticArrays, and GPUArrays.

[mcabbott]

Needs JuliaArrays/StructArrays.jl#292

[christiangnrd]

StructArrays v0.6.17 with compat for Adapt v4 has been released

[roflmaostc]

What exactly holds this back?

[mcabbott]

Many tests failed when last I ran them. Perhaps this PR just needs to be rebased on master, if those are fixed in the meantime?

[christiangnrd]

The tests are unrelated to this patch. I've run the test suite on main and on main with Adapt 4 and the exact same tests fail. This could probably be merged and hopefully released soon as it's blocking a few downstream PRs.

[mcabbott]

The same tests as fail on CI, or different ones?

On CI it's all about one / zero, for which there were various recent PRs. But I don't have bandwith to dig into this.

Am a bit reluctant to release things with tests failing, regardless of assurances that it's no worse than before.

[christiangnrd]

Understandable. I reran tests for both versions on Macos and Linux (4 runs total) and they're all erroring the same as the CI for Julia 1.10 on x64.

The one / zero errors were fixed by #773. A rebase of this PR should show the same 1 failure and 8 errors as #773

While those were running, I also fixed new CI failures in a separate PR (#776) that should be a quick review.

[oxinabox]

Passing on 1.6 x64. x86 timed out

And the remaining failures on 1.10 are preexisting. (and have fixes)