Outdated method of specifying path to siad in README

[starius]

README.md says:

If it's outside of your path, provide its location using the -siad flag. For all flags, see sia-antfarm -h.

Option -siad doesn't work. sia-antfarm -h prints the following:

Usage of sia-antfarm:
  -config string
        path to the sia-antfarm configuration file (default "config.json")

The option seems to be replaced with a setting in the config file:

Sia-Ant-Farm/sia-antfarm/ant.go

Line 189 in ccf3055

if config.SiadPath == "" {