Added QEMU to run ARM64 container

Author: cmaglie

Diff for: DistTasks.yml

@@ -208,6 +208,8 @@ tasks:
     desc: Builds Mac OS X ARM64 binaries
     dir: "{{.DIST_DIR}}"
     cmds:
+      # Install QEMU to run ARM64 binaries on x86_64
+      - docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
       # "git config safe.directory" is required until this is fixed https://github.com/elastic/golang-crossbuild/issues/232
       - |
         docker run -v `pwd`/..:/home/build -w /home/build \