[IDEA] Include Apple M1 in releases

[kikito]

Is your feature request related to a problem? Please describe.
I'd like to be able to use grpcbin on Apple M1s without having to use the (sometimes unreliable) translation layer.

Describe the solution you'd like
Ideally I would like "grpcbin_Darwin_arm64.tar.gz" to appear in the releases

Describe alternatives you've considered
I think all this might need is modifications of the goreleaser.yml file. I have given it a look but I don't understand exactly how that yml generates the list of release files that grpcbin has.

Additional context
Goreleaser is supposed to support Apple M1s now: goreleaser/goreleaser#1952

Thank you!

[aboudreault]

@moul I have been able to produce the m1 binary (grpcbin_Darwin_arm64.tar.gz) in our private repo. However, it is not clear what I would have to do, and how I could test goreleaser to push a multi-arch image. Is this something you could help with?

kong repo: https://github.com/Kong/grpcbin
Changes to get the arm64 m1 binary: https://github.com/Kong/grpcbin/pull/1/files