code: func VersionCommand(factory app.ProjectFactory) cli.Command {
  	return cli.Command{
  		Name:   "version",
  		Usage:  "Show version informations",
  		Action: app.Version,
  		Flags: []cli.Flag{
  			cli.BoolFlag{
  				Name:  "short",
  				Usage: "Shows only Compose's version number.",
  			},
  		},
  	}
  }
docs: // VersionCommand defines the libcompose version subcommand.