This is a tool that is used internally by urfave/cli to generate
flag types and methods from a YAML input. It intentionally pins
usage of github.com/urfave/cli/v2 to a release rather than
using the adjacent code so that changes don't result in this tool
refusing to compile. It's almost like dogfooding?
This tool is maintained as a sub-project and is not covered by the API and backward compatibility guaranteed by releases of urfave/cli.