Fix docker run does not recognize previously pulled image

When you pull an image from a registry and specify both a tag and a digest,
docker does not seem to tag it locally. This leaves the image unable to
be run if both the tag and the digest are specified to `docker run`.
But it will run if only by the digest is specified.

Author: triarius

packer/linux/conf/bin/bk-configure-docker.sh

@@ -81,7 +81,7 @@ if ! docker run \
   --userns=host \
   --rm \
   --pull=never \
-  "tonistiigi/binfmt:${QEMU_BINFMT_TAG}" \
+  "tonistiigi/binfmt@${QEMU_BINFMT_DIGEST}" \
     --install all; then
   echo Failed to install binfmt
   docker image ls