Add event_ts field on all "inner events"
Description
Currently (as of 93035c946040f00b2eb69dc9a954f83a9803e931) the EventTimestamp field is only present on some inner events types. According to the OpenAPI specs, the event_ts field should be present along with type on all inner events.
(Optional) Slack's documentation
https://github.com/slackapi/slack-api-specs/blob/master/events-api/slack_events_api_async_v1.json#L30
The web docs don't mention that event_ts should be present, but I can verify that it actually is.
The slack-api-specs repository is not maintained precisely as far as I can see. So if you want to know the latest specifications, you can look at the official SDKs for Node.js and Java.
ah good thanks for the pointer to the Java SDK. I updated https://github.com/slack-go/slack/pull/1052 to not add event_ts on the grid migration events, since those don't seem to have that field according to the Java SDK.
I wonder if one could hack a quick&dirty parser to generate the Go models from the Java ones :shrug: