Provide prebuilt binaries for arm64 linux.

[pepyakin]

AFAICT, risc0 targets to support first class DX on linux and macOS.

To quote this

Note that the following pre-built host targets are available:

• aarch64-apple-darwin
• x86_64-apple-darwin
• x86_64-unknown-linux-gnu

however, binaries for aarch64-unknown-linux-gnu are not provided. It's not only a problem for linux but it's also a problem for macOS users since docker would run under aarch64.

IMO, those lines should work without compiling under docker running under macOS on apple silicon.

cargo binstall risc0
cargo risczero install

[flaub]

We currently don't have any arm64 linux machines in our CI, so that would be required for us to do that here. Perhaps in the future this will make sense.