Apple Silicon M1 quarantine of MacOS arm64 builds

[adamkdean]

MacOS arm64 builds seem to be broken. They display the "App is damaged" message, which is due to quarantine, which I think is due to a signing issue. This can be fixed with, for example, sudo xattr -rd com.apple.quarantine /usr/local/bin/edge but there must be an issue with the build or signing process.

This has worked before, so I'm not sure what has changed to stop it working again.

[adamkdean]

> Warning Unable to sign the macOS executable
  Due to the mandatory code signing requirement, before the
  executable is distributed to end users, it must be signed.
  Otherwise, it will be immediately killed by kernel on launch.
  An ad-hoc signature is sufficient.
  To do that, run pkg on a Mac, or transfer the executable to a Mac
  and run "codesign --sign - <executable>", or (if you use Linux)
  install "ldid" utility to PATH and then run pkg again

Previously worked (see https://github.com/edge/cli/blob/master/.ci/docker/build#L45-L50) but for some reason stopped working.