Fixes for CI from @code-asher's review

ci/release-container/build.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+main() {
+  cd "$(dirname "$0")/../.."
+  source ./ci/lib.sh
+  VERSION="$(pkg_json_version)"
+
+  imageTag="codercom/code-server:$VERSION"
+
+  docker build -t "$imageTag" -f ./ci/release-container/Dockerfile .
+}
+
+main "$@"