VOICE_SERVER_UPDATE_FAIL event

[sevenc-nanashi]

We can't know the voice server update is failed, or discord is being late for it.
So if there's VOICE_SERVER_UPDATE_FAIL event, it will be good.

{
  "t": "VOICE_SERVER_UPDATE_FAIL",
  "s": 2,
  "op": 0,
  "d": 1337
  "$note": "that 1337 will change by reason, such as No permissions, Full, and more."
}