STS AutoRefreshingProvider does not recover from failure

[nbaztec]

Bug

STS AutoRefreshingProvider caches errors and never initiates a reconnect until session expiry

Expected Behavior

Errors are not cached

Actual Behavior

Errors are cached for entire session (default: 1hr)

Version

rust: 1.51.0 rusoto: 0.46.0

Related

#1874