Add arm64 builds for linux and darwin

[bartekpacia]

Use case

I tried to run make ensure-gfmrun while working on urfave/cli on my Apple Silicon Mac but encountered this:

$ make ensure-gfmrun
go run scripts/build.go  ensure-gfmrun
# ---> /opt/homebrew/bin/git rev-parse --show-toplevel
# ---> /Users/Bartek.Pacia/projects/cli/.local/bin/gfmrun --version
2024/11/02 22:16:20 download file from https://github.com/urfave/gfmrun/releases/download/v1.3.0/gfmrun-darwin-arm64-v1.3.0 into /Users/Bartek.Pacia/projects/cli/.local/bin/gfmrun: response 404
exit status 1
make: *** [ensure-gfmrun] Error

[bartekpacia]

why is CI red?

[dearchap]

This is what the error says

Error: example-L54.go:7:3: no required module provides package golang.org/x/example/stringutil; to add it:
	go get golang.org/x/example/stringutil

[bartekpacia]

thanks!

seems related golang/go#61722