Promote EndpointSlice API test to Conformance

[swetharepakula]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This PR promotes the last EndpointPoint Slice API e2e test to conformance.

Special notes for your reviewer:

This e2e test was introduced into testgrid on 3/10: https://testgrid.k8s.io/sig-release-master-blocking#gce-cos-master-default&include-filter-by-regex=EndpointSlice&width=5 and has been flake free. It will qualify on 3/24 and this PR can be merged then.

This will add the remaining coverage needed for the v1 EndpointSlice APIs:
https://apisnoop.cncf.io/1.21.0/stable/discovery

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

KEP: EndpointSlice KEP
Enhancement Issue: kubernetes/enhancements#752

/sig network
/sig testing
/cc @Riaankl @hh @robscott @aojea
/assign @thockin

[robscott]

Thanks!

/lgtm
/cc @johnbelamaric

[Riaankl]

/triage accepted

[Riaankl]

@dims Please add to milestone 1.21
This promotion address endpoints graduated to GA in 1.21 but still do not have conformance tests.

Thank you @swetharepakula

[dims]

/milestone v1.21

[johnbelamaric]

I'm satisfied.
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: johnbelamaric, swetharepakula

The full list of commands accepted by this bot can be found here.

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Needs approval from an approver in each of these files:

• test/conformance/testdata/OWNERS [johnbelamaric]
• test/e2e/network/OWNERS [johnbelamaric]

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[Riaankl]

/test pull-kubernetes-e2e-kind-ipv6
Unrelated flake

• Failure [55.787 seconds]
[sig-node] Probing container
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/test/e2e/common/node/framework.go:23
  should be ready immediately after startupProbe succeeds [It]
  /home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/test/e2e/common/node/container_probe.go:380
skipped 19431 lines unfold_more
[Fail] [sig-node] Probing container [It] should be ready immediately after startupProbe succeeds 
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/github.com/onsi/ginkgo/internal/leafnodes/runner.go:113

[Riaankl]

/test pull-kubernetes-e2e-kind
Unrelated flake

Kubernetes e2e suite: [sig-node] InitContainer [NodeConformance] should not start app containers if init containers fail on a RestartAlways pod [Conformance] expand_less | 5m3s
-- | --
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/test/e2e/framework/framework.go:630 Mar 22 19:29:17.017: Unexpected error:     <*errors.errorString \| 0xc00024a250>: {         s: "timed out waiting for the condition",     }     timed out waiting for the condition occurred /home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/test/e2e/common/node/init_container.go:432

[Riaankl]

APISnoop was updated and all EndpointSlice endpoint now have Conformance tests.
https://apisnoop.cncf.io/1.21.0/stable/discovery