node: Add Windows ARM64 prebuilds to CI

[dennisameling]

This PR adds prebuilds for Windows ARM64 to CI. I've been building these in my fork for a few months and haven't encountered issues with it.

As discussed in #426 (comment), "discussion with the Desktop folks is leaning positive about it", so I took the liberty to create this PR 😊

[jrose-signal]

Thanks for the ping! Yes, we can take this, but I'll note this workflow is just for the manually-submitted job to publish to NPM; we're still not compiling for aarch64-apple-darwin or aarch64-pc-windows-msvc on every PR. With macOS I didn't worry about it because we do compile the non-bridge crates for aarch64-apple-ios; do you feel confident that aarch64-pc-windows-msvc is sufficiently exercised by the other AArch64 platforms + AMD64 Windows?

[jrose-signal]

Let's make this a little more semantic: we can rename additional-rust-target to arm64-rust-target and then this can check whether arm64-rust-target is present at all.

[dennisameling]

Makes sense! Updated in a2b1ae1 - seems to work correctly: https://github.com/dennisameling/libsignal-client/runs/4893965003?check_suite_focus=true

[dennisameling]

do you feel confident that aarch64-pc-windows-msvc is sufficiently exercised by the other AArch64 platforms + AMD64 Windows?

I would say yes. I've been building this in my fork for a few months from a x64 host and all is good. aarch64-pc-windows-msvc is a Tier 2 with Host Tools platform, just like aarch64-apple-darwin, so it's also well-supported from the Rust side.

we're still not compiling for aarch64-apple-darwin or aarch64-pc-windows-msvc on every PR

Would you like me to add aarch64-pc-windows-msvc to the regular PR pipeline as well? Shall we simply use npx prebuildify for that or would you prefer a different approach? I'm happy to sponsor an ECS LIVA QC710 if you want to run CI tests on Windows ARM64 as well, or would you feel comfortable enough cross-compiling from x64 for now (which is the only architecture for which GH Actions has hosted runners currently)?

[jrose-signal]

Let's leave the per-PR CI as it is for now, then. Setting up a custom GitHub Actions runner is one more thing we'd have to keep running, and without that we'd just be testing compilation, which is pretty unlikely to break just for ARM64 Windows.

Thank you for doing this!

[jrose-signal]

Just published v0.12.1 with an ARM64 Windows prebuild. :-)