Send to Slack (webhook)

  webhookURL: string, // mandatory
  message:    string, // mandatory
  sender:     string, // optional
  icon:       string  // optional
): boolean

This function posts a notification to a Slack channel via Slack's "Incoming WebHooks".

The webhookURL and message parameters are mandatory. You may, if you wish, also specify a sender (free-text string), and an icon name using the standard emoji icon name format.

This function returns true if the notification was successfully posted to the desired Slack channel, otherwise it returns false.


    'Some message', ' AFT!', ':smile:');