message: create-app: update Dockerfile to indicate need for BuildKit to be enabled
diff: @@ -20,6 +20,10 @@ RUN apt-get update && \
  # From here on we use the least-privileged `node` user to run the backend.
  USER node
  +
  +# This should create the app dir as `node`.
  +# If it is instead created as `root` then the `tar` command below will fail: `can't create directory 'packages/': Permission denied`.
  +# If this occurs, then ensure BuildKit is enabled (`DOCKER_BUILDKIT=1`) so the app dir is correctly created as `node`.
  WORKDIR /app
  # This switches many Node.js dependencies to production mode.
  