Automate release process

ci/steps/publish-docker.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+main() {
+  cd "$(dirname "$0")/../.."
+  source ./ci/steps/lib.sh
+
+  if [[ ${CI-} ]]; then
+    echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin
+  fi
+
+  download_artifact release-packages ./release-packages
+  ./ci/release-container/push.sh
+}
+
+main "$@"