Update terminal-notifier and expose new APIs

[jpillora]

See new repo https://github.com/julienXX/terminal-notifier

Now notification actions are exposed, would be handy to have a Go API to use it

[deckarep]

Specifically can you list what new APIs you're interested in?

[jpillora]

Hey sorry for the delay. In order of interest, it'd be nice to have:

1. -actions and -dropdownLabel (provide a set of options, return the clicked option)
2. -reply (should give a text box, return the text on "send")
3. -active/group/remove ID (maybe this could be abstracted away somehow, a simple Notification.Remove method would be nice)

[deckarep]

Thanks @jpillora - I think these changes are good but for now I've labeled this as help-wanted. I currently don't have much time to maintain this package in particular.

[jpillora]

No worries, I understand!