spike: add arm64 binary builds

[ghost]

To Do

• pkg needs an arm64 environment to build arm64 binaries.
  • https://circleci.com/docs/2.0/arm-resources/
    • Can disable bytecode generation at the cost of performance.
  • Alternatively, setup QEMU (binfmt) and ldid on our CircleCI env. This is probably easiest.
• pkg macos-arm64 support is "experimental"
• NodeJS doesn't have Windows/arm64 (is that even a thing?)
  • https://nodejs.org/download/release/latest-v16.x/
• NodeJS only supports darwin-arm64 from Node 16 onwards.
  • https://nodejs.org/dist/latest-v16.x/
• We need an M1 machine to manually test against. (and for general customer support)
  • CircleCI and GitHub Actions don't support M1 environments.
    • Support for VMs on Apple M1 actions/runner-images#2187
    • https://circleci.canny.io/cloud-feature-requests/p/support-new-m1-arm-based-macs
  • AWS EC2 supports M1, but it's in early preview, invite-only and isn't wired into our test pipeline.
    • Announced Dec 2021. Expect bugs even if we get an invite.
    • https://aws.amazon.com/ec2/instance-types/mac/
• macOS arm64 binaries MUST be signed, otherwise they're useless.
  • x64 binaries just show a warning, arm64 binaries won't run at all.
  • pkg attempts "ad-hoc" signing which they say should be enough. Not sure what kind of UX that results in.
  • Might be a good chance to move away from the custom mac tarball.
  • https://developer.apple.com/documentation/macos-release-notes/macos-big-sur-11_0_1-universal-apps-release-notes