Speed up multi-arch builds

[mustafaakin]

arm64 builds are very slow. Takes around 30 minutes due to using docker buildx creating an emulated arm64 image. We can modify the build to use GOARCH=arm64 and just copy the file to a Docker image which should be much faster - compiling lots of huge dependencies in emulated VM is slow.

[grzesuav]

actually I got pretty good result with using goreleaser to do multi arch build and wrap them - https://github.com/grzesuav/metacontroller/releases/tag/v1.3.0 see https://github.com/grzesuav/metacontroller/runs/7771499943?check_suite_focus=true Release step - it takes 8 minutes to do that end to end