I have an upcoming PR for event notifications that needs similar
exponential backoff logic, and I prefer the API and logic in the
auto-auth exponential backoff rather than that of
github.com/cenkalti/backoff/v3.
This does have a small behavior change: the auto-auth min backoff
will now be randomly reduced by up to 25% on the first call. This is
a desirable property to avoid thundering herd problems, where a bunch
of agents won't all try have the same retry timeout.
