Add support for the /opt/homebrew prefix
Add support for the /opt/homebrew prefix

Homebrew for ARM Macs will support installation into the /opt/homebrew prefix, instead of /usr/local.

This patch updates our path code to accept both on Apple silicon, but only the former in amd64 builds, allowing for two installations on the same machine if desired.

buildkite/agent,buildkite/agent,buildkite/agent