I know nothing about this project, but this appears to be using a docker image from here "https://github.com/dockur/windows/pkgs/container/windows".
Which says "Any product keys found in the code are just generic placeholders provided by Microsoft for trial purposes."
This app appears to be using windows with trial keys which goes against their intended usage and would have questionable legality. I would think if you do use this you would need to have a licensed version of windows and alter the docker settings to use your purchased key instead of the included trial keys.
Ideally this project would have this detail in big bold letters in it's README.