Use iso8601 helper

Report number of cleared sessions more accurately

Report number of cleared sessions more accurately

Merge pull request 99designs#646 from 99designs/configurable-expiry-w…

…indow

Add AWS_MIN_TTL to set expiry window

Fix error returned by OIDCTokenKeyring

Fix gc strategy to ensure we don't return expired credentials

Merge pull request 99designs#631 from ajkerrigan/oidc-cache-fix

Handle OIDC caching for new keyring entries

Handle shutdown via kill properly

Add logging for 99designs#624

Clarify credential_process