Change volume and brightness in quarter-step doesn't work

[CloudnuY]

• Robotgo version (or commit ref): v0.46.0.400, Pyrenees Mountains!
• Go version: 1.10
• Gcc version: Apple LLVM version 9.0.0 (clang-900.0.39.2)
• Operating system and bit: macOS 10.12.6
• Can you reproduce the bug at Examples:
  • Yes (provide example code)
  • No
  • Not relevant
• Provide example code:

  package main
  
  import (
      "github.com/go-vgo/robotgo"
  )
  
  func main() {
      arr := []string{"alt", "shift"}
      robotgo.KeyTap("audio_vol_down", arr)
  }

• Log gist:
  Null

Description

http://hints.macworld.com/article.php?story=20130309231013323

On macOS, ⌥+⇧+F1 lowers the brightness by a quarter of a notch, but there's no way to do that with this library.

[vcaesar]

I test on my mac 10.13.3 is normal work. ⌥+⇧+F1 without the same effect, I will update it.