upgrade.sh

#!/usr/bin/env bash
# shellcheck disable=SC2312 # (info): Consider invoking this command separately to avoid masking its return value (or use '|| true' to ignore).

set -e

if command -v curl >/dev/null; then
  # -sq == --silent --disable
  dl="curl -sq"
else
  # -q0 == --quiet --output-document
  dl='wget --no-config -qO -'
fi

ALPINE_VER=$(${dl} 'https://registry.hub.docker.com/v2/repositories/library/alpine/tags/' | jq -r '.results[1].name')
GH_VER=$(${dl} https://api.github.com/repos/cli/cli/tags | jq -r '.[0].name')
SHELLCHECK_VER=$(${dl} https://api.github.com/repos/koalaman/shellcheck/tags | jq -r '.[0].name')
SHFMT_VER=$(${dl} https://api.github.com/repos/mvdan/sh/tags | jq -r '.[0].name')

GH_VER="${GH_VER/v/}"
SHELLCHECK_VER="${SHELLCHECK_VER/v/}"
SHFMT_VER="${SHFMT_VER/v/}"

sed -Ei "
s/^(FROM\s+alpine:).*/\1${ALPINE_VER}/;
s/^(ARG\s+gh_version=).*/\1${GH_VER}/;
s/^(ARG\s+shellcheck_version=).*/\1${SHELLCHECK_VER}/;
s/^(ARG\s+shfmt_version=).*/\1${SHFMT_VER}/;
" Dockerfile

git diff