Varnish Controller 6.6.3 Release

Note: Only nats, router and api-gw requires upgrading for this patch release, see versioning.

• Update nats-server due to CVE-2024-45337.
• Update golang.org/x/net for API-GW and Traffic Router due to CVE-2024-45338.

See Varnish Controller Changelog for more details on the changes and the upgrade notes for more details on how to upgrade.