Add a supported versions to the main page.

[timothysc]

We will need to create a support matrix due to issues we have been finding, and will need to patch the upstream tests.

We have found some issues in field level versioning :

/go/src/k8s.io/kubernetes/_output/dockerized/go/src/k8s.io/kubernetes/test/e2e/common/downward_api.go:94
Error creating Pod
Expected error:
    <*errors.StatusError | 0xc4212f9d40>: {
        ErrStatus: {
            TypeMeta: {Kind: "", APIVersion: ""},
            ListMeta: {SelfLink: "", ResourceVersion: "", Continue: ""},
            Status: "Failure",
            Message: "Pod \"downward-api-e1e7a01c-a93e-11e7-93c2-0a580ac00202\" is invalid: spec.containers[0].env[1].valueFrom.fieldRef.fieldPath: Invalid value: \"status.hostIP\": error converting fieldPath: field label not supported: status.hostIP",
            Reason: "Invalid",
            Details: {
                Name: "downward-api-e1e7a01c-a93e-11e7-93c2-0a580ac00202",
                Group: "",
                Kind: "Pod",
                UID: "",
                Causes: [
                    {
                        Type: "FieldValueInvalid",
                        Message: "Invalid value: \"status.hostIP\": error converting fieldPath: field label not supported: status.hostIP",
                        Field: "spec.containers[0].env[1].valueFrom.fieldRef.fieldPath",
                    },
                ],
                RetryAfterSeconds: 0,
            },
            Code: 422,
        },
    }
    Pod "downward-api-e1e7a01c-a93e-11e7-93c2-0a580ac00202" is invalid: spec.containers[0].env[1].valueFrom.fieldRef.fieldPath: Invalid value: "status.hostIP": error converting fieldPath: field label not supported: status.hostIP
not to have occurred
/go/src/k8s.io/kubernetes/_output/dockerized/go/src/k8s.io/kubernetes/test/e2e/framework/pods.go:76

[timothysc]

@abiogenesis-now

Well have to outline versions and support given some of the issues and update on later patch release(s).

[jesscodez]

@timothysc to clarify: are these issues with thee2e tests? Or with certain versions of Kubernetes not playing well with Sonobuoy?

(And I'm lacking a bit of context---are there links to issues that I can read up on? I don't have enough knowledge to be actionable at the moment)

[timothysc]

@abiogenesis-now The 1.8 Conformance-e2e tests leverage some api fields that don't exist in 1.6 and as a result the test fails. So far we've only come across 1 test that has this issue.