Features for v4 release

[dearchap]

List of TODOs, features for v4 release

1. Remove hack for HelpFlag - #2176
2. Add support for marshall/unmarshaller types #2051
3. Rework help subsystem templating to be easier to manage #2075

[GoodiesHQ]

I would love to know if numerical flags would ever be supported. Not sure if there's an existing issue for this (I suspect there probably is) but being able to add -4 or -6 right now requires manual workaround.

args := make([]string, 0, len(os.Args))

for _, arg := range os.Args {
	switch arg {
	case "-4":
		args = append(args, "--ipv4")
	case "-6":
		args = append(args, "--ipv6")
	default:
		args = append(args, arg)
	}
}

err := app.Run(ctx, args)