Provide multi-platform docker images under a single tag

#!/bin/sh

set -e

VERSION="$1"

test -n "${VERSION}"

git checkout main

git pull

git checkout "${VERSION}"

git submodule update --init

docker buildx build --push --no-cache --platform linux/amd64,linux/arm64 --tag derfnull/db-fakedisplay:${VERSION} --tag derfnull/db-fakedisplay:latest --build-arg=dbf_version=${VERSION} .