code: public Actions keyUp(CharSequence key) {
      if (isBuildingActions()) {
        action.addAction(new KeyUpAction(jsonKeyboard, jsonMouse, asKeys(key)));
      }
  
      return addKeyAction(key, codePoint -> tick(defaultKeyboard.createKeyUp(codePoint)));
    }
docs: Performs a modifier key release. Releasing a non-depressed modifier key will yield undefined
  behaviour.
  
  @param key Either {@link Keys#SHIFT}, {@link Keys#ALT} or {@link Keys#CONTROL}.
  @return A self reference.