spf13/cobra Providing conditional default values

conditonalDefaultsCobra.go

## Question
Suppose i have a command cmd
```
cmd --opt1=['public'|'private'] --opt2=[true|false]
```

How do i define `--opt2` defaut value to `false` if `--opt1` is `public`
and `--opt2` default value to `true` if `--opt1` is `private` ?


## Answer
Do below in your Run()
````
o1v := flagSet.GetString("opt1")
o2changed := flagSet.Changed("opt2")

if o2changed {
    return
}

if o1v == "public" {
    flagSet.Set("opt2", "false")
} else if o1v == "private" {
    flagSet.Set("opt2", "true")
}
````