A Pull Request should be associated with an Issue.

Related issue: #1105

Description

Now that developers are using different architectures (amd64 and arm64, basically), we need to use different binaries adapted for those architectures.

This PR changes build.sh script, adding binaries for linux/arm64 and darwin/arm64

I needed to rename the .tar.gz files to indicate the architecture. Now its naming is:

./gh-ost-binary-${osshort}-${GOARCH}-${timestamp}.tar.gz