custom domain for version 6.3.x.x

[blueprismo]

Is your feature request related to a problem? Please describe. Hello! I need three pinned versions for shopware (6.3, 6.4, 6.5) in a k8s testing environment. the two latter ones are OK. For the first one (6.3.x.x) the SHOP_DOMAIN

Describe the solution you'd like I would love to be able to have a custom domain configurable as environment variables in image versions 6.3.X.X I have tried both APP_URL and SHOP_DOMAIN and neither of them work

Describe alternatives you've considered modify an entrypoint script or some dirty workaround I don't wanna do.

Additional context 😃