Previously this would truncate to the nearest integer, which could
result in clients retrying before the quota has reset, and getting rate
limited again. This also includes an update from go-rate that will round
up when reporting the reset time for the RateLimit header.
Note that in the case of a 503, the Retry-After header was already being
set correctly.
See: https://github.com/hashicorp/go-rate/pull/8
Timothy Messier