This project is being retired. Prebuilt CrafterCMS Docker Images are available on Docker Hub. To manually build your own, use the main project CrafterCMS. For instructions, see the README.
For example, to build Docker Images for v4.1.5, you can do this:
git clone -b v4.1.5 https://github.com/craftercms/craftercms v4.1.5
cd v4.1.5
./gradlew build deploy bundle buildMainImages