v0.1.6

Fixed

• Docker multi-arch image was broken in v0.1.5: the build matrix
  (linux/amd64, linux/arm64) made each job push to the same tag, the
  last writer winning. Resulting manifest only had arm64 (docker pull
  on x86 returned "no matching manifest for linux/amd64"). Replaced with a
  single Buildx job that emits a real multi-arch manifest list.