Create check run: documented conclusion=skipped does not work

https://developer.github.com/v3/checks/runs/#create-a-check-run claims that skipped is a valid value for conclusion yet when I actually try to use it (on github.com) I get

Invalid request.

skipped is not a member of ["success", "failure", "neutral", "cancelled", "timed_out", "action_required"].

Bump. I’ve also come up against the same issue. Did you ever get to the bottom of this, @jglick?

No, I have not rechecked this.