`file_change`: key "timestamp" not present

[bwbaugh]

Example 1:

"{\"type\":\"file_change\",\"file_id\":\"FREDACTED\",\"user_id\":\"UREDACTED\",\"file\":{\"id\":\"FREDACTED\"},\"event_ts\":\"1526333100.000242\"}"
Error in $.file: key "timestamp" not present
Please report this failure to the github issue tracker

Pretty printed JSON:

{
  "event_ts": "1526333100.000242",
  "file": {
    "id": "FREDACTED"
  },
  "file_id": "FREDACTED",
  "type": "file_change",
  "user_id": "UREDACTED"
}

---

Example 2:

"{\"type\":\"file_change\",\"file_id\":\"FREDACTED\",\"user_id\":\"UREDACTED\",\"file\":{\"id\":\"FREDACTED\"},\"event_ts\":\"1526333110.000564\",\"ts\":\"1526333110.000564\"}"
Error in $.file: key "timestamp" not present
Please report this failure to the github issue tracker

Pretty printed JSON:

{
  "event_ts": "1526333110.000564",
  "file": {
    "id": "FREDACTED"
  },
  "file_id": "FREDACTED",
  "ts": "1526333110.000564",
  "type": "file_change",
  "user_id": "UREDACTED"
}