Update SCS-0219 after retirement of ingress-nginx and add Gateway API

[lucasrattz]

This pull request fixes #1097

[depressiveRobot]

Thank you for the PR. Looks good to me from a formal point of view. However, I think someone from the Team Container should have a look here and review it. @jschoone @janiskemper

[berendt]

Don't we need a new version of this document here?

https://docs.scs.community/standards/scs-0001-v1-sovereign-cloud-standards#stabilized-phase-stable

"If a breaking change to an existing SCS document is deemed necessary, a new document with a new number shall be created and the old document SHOULD be deprecated."

[depressiveRobot]

To me, this is more about a fix and adding a recommendation than a breaking change. So no need for a new version, IMO.

[jklare]

Since the Ingress API will continue to exist (https://gateway-api.sigs.k8s.io/faq/#will-gateway-api-replace-the-ingress-api) and the Gateway API is basically just an entirely new and independent parallel implementation, we can probably not just replace one with another in the standards (since this is not an update, but a switch towards another implementation).

[mbuechse]

@jklare You're right. The point here is that we're only replacing one recommendation by another (if I'm not mistaken). This is not a breaking change, because every test subject that passes the old version will also pass the new one. The update is with respect to Traefik instead of nginx.

[berendt]

Adding a new normative SHOULD ("CSPs SHOULD offer support for the Gateway API …") is, in my understanding, a substantive extension of the normative requirements for CSPs, which requires a v2 if the document has already been stabilized.

[mbuechse]

@berendt If this matter is so controversial, we should discuss it more. I added it to the agenda of this week's SIG Std/Cert.