Quay: stripe webhook accepts forged events without signature verification in quay

A flaw was found in Red Hat Quay's Stripe billing webhook handler. This vulnerability allows an unauthenticated attacker to forge billing events by sending crafted JSON requests to the `/webhooks/stripe` endpoint without validating the Stripe-Signature header. Successful exploitation can lead to the unauthorized resetting of a namespace's build quota to its maximum and trigger unsolicited billing emails to namespace administrators.