error starting new jumpstart app

Hi

I just created new rails app using free jumpstart template

https://github.com/excid3/jumpstart

I receive an error when starting the. project about missing build script

✘  myapp   master  bin/dev
18:09:56 web.1 | started with pid 50913
18:09:56 js.1 | started with pid 50914
18:09:56 css.1 | started with pid 50915
18:09:56 js.1 | yarn run v1.22.10
18:09:56 css.1 | yarn run v1.22.10
18:09:56 css.1 | $ sass ./app/assets/stylesheets/application.bootstrap.scss ./app/assets/builds/application.css --no-source-map --load-path=node_modules --watch
18:09:56 js.1 | error Command "build" not found.
18:09:56 js.1 | info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
18:09:57 js.1 | exited with code 1
18:09:57 system | sending SIGTERM to all processes
18:09:57 css.1 | exited with code 1
18:09:57 web.1 | terminated by SIGTERM

Upgrading to the latest version of Node help me with the same problem on Ubuntu 20.04.
curl -sL https://deb.nodesource.com/setup_18.x | sudo -E bash -