Adding Docker buildx to support arm64 docker builds (#755)
Adding Docker buildx to support arm64 docker builds (#755)

* adding docker buildx to support arm64 images

* optionally create buildx builder

* using build use to ensure multi-arch builder is selected

* fixing typos
scalyr/scalyr-agent-2,scalyr/scalyr-agent-2,scalyr/scalyr-agent-2,scalyr/scalyr-agent-2