feat(dns): Add zeroconf client options to DNS params

[gabe565]

Hey! CastSponsorSkip dev here. I have some reports of errors due to zeroconf trying to bind to an IPv6 address when IPv6 is disabled in gabe565/CastSponsorSkip#54. I suspect zeroconf.SelectIPTraffic could help, so this PR adds support for variadic parameters. This also allows for selecting multiple interfaces, by leaving the iface param set to nil, then passing zeroconf.SelectIfaces directly.

Honestly, it would probably be best practice to remove the iface param, but that would be a breaking change. If you prefer, I could change this PR to do something like this:

func DiscoverCastDNSEntries(ctx context.Context, iface *net.Interface) (<-chan CastEntry, error) {
	var opts []zeroconf.ClientOption
	if iface != nil {
		opts = append(opts, zeroconf.SelectIfaces([]net.Interface{*iface}))
	}
	return DiscoverCastDNSEntriesV2(ctx, opts...)
}

func DiscoverCastDNSEntriesV2(ctx context.Context, opts ...zeroconf.ClientOption) (<-chan CastEntry, error) {
	resolver, err := zeroconf.NewResolver(opts...)
	if err != nil {
		return nil, fmt.Errorf("unable to create new zeroconf resolver: %w", err)
	}
        [...]

[vishen]

@gabe565 Just wondering if this was meant to be closed?