Schema for multimaps is wrong

[xRodney]

Describe the bug

Hello again,

after #4413 will have been merged, crd generator will no longer fail on multimaps, which are present in keycloak-operator crds.

Unfortunately, they will still be generated wrong.

Fabric8 Kubernetes Client version

SNAPSHOT

Steps to reproduce

(same as in #4357)

@Group("map.fabric8.io")
@Version("v1alpha1")
public class ContainingMaps extends  CustomResource<ContainingMapsSpec, Void> {}

public class ContainingMapsSpec {
  private MyMultiMap<String, String> test3;
}

public class MyMultiMap<K, V> extends HashMap<K, List<V>> {}

The field test3 is treated as if it was Map<String, String>:

      openAPIV3Schema:
        properties:
          status:
            type: object
          spec:
            properties:
              test3:
                additionalProperties:
                  type: string
                type: object

Expected behavior

The field test3 should be treated as if it was Map<String, List<String>>:

 openAPIV3Schema:
        properties:
          status:
            type: object
          spec:
            properties:
              test3:
                additionalProperties:
                  items:
                    type: string
                  type: array
                type: object

Runtime

other (please specify in additional context)

Kubernetes API Server version

other (please specify in additional context)

Environment

other (please specify in additional context)

Fabric8 Kubernetes Client Logs

No response

Additional context

Compared to #4413, this is rather low severity, as it can easily be worked around using @SchemaFrom and/or @SchemaSwap.

In my assessment, this should be improved in sundrio and I have already filed an issue there (sundrio/sundrio#341) and a PR (sundrio/sundrio#342). If I'm right and my contribution is merged, here we should only upgrade sundrio and maybe add a test and a changelog entry.