Distribute pre-built binaries for cargo-apk

[notgull]

At the moment, winit's CI pipeline builds or caches a fresh copy of cargo-apk for Android. It would be cleaner to instead just install the binary through install-action or cargo-binstall.

However, cargo apk does not distribute binaries that can be installed. It would be better if pre-built binaries of cargo-apk were distributed through GitHub Actions, so that they can be easily installed by users.

See here for an example of how this can be done automatically through a release pipeline. I am willing to write the CI code, but I need cooperation from a @rust-mobile admin to handle setting up secret keys.

[MarijnS95]

cargo-apk has been deprecated some years ago in favour of xbuild, so I don't think I would spend time engineering such a thing. There isn't even enough time to get xbuild on-par with cargo-apk in certain areas.

[notgull]

cargo-apk has been deprecated some years ago in favour of xbuild,

Hmm, I wasn't aware of this. It should probably be signaled better in this repository, as winit still uses it in CI.

[MarijnS95]

It looks like it got "lost" (or rather, not a purpose-made one added) when this repo was split out from the main ndk/android-ndk-rs repo.