Description:

Refer to https://github.com/quay/quay/blob/redhat-3.9/config.py#L829. the default value of "FEATURE_SECURITY_SCANNER_NOTIFY_ON_NEW_INDEX" is false.

If customer doesn't set "FEATURE_SECURITY_SCANNER_NOTIFY_ON_NEW_INDEX: true" manually,  when set notification for Package Vulnerability Found, it won't work as expected. 

It is better to describe this attribute in detail  in quay official document, because set notification for Package Vulnerability Found is a very common use case.