Test-infra: Deprecate and drop support for OWNERS assignees

[spiffxp]

I think it's now "eventually" https://github.com/kubernetes/contrib/pull/2076/files#r90728711

assignees are effectively approvers as far as mungegithub is concerned, and I've been unable to find anything else that consumes OWNERS files

Repos that use assignees are doing so either out of legacy or because they don't care to have two-stage reviews. Either way, the default setting for use-reviewers will have them covered if we just blanket rename assignees to approvers in the offending OWNERS files

@kubernetes/kops-maintainers @kubernetes/sig-docs-maintainers @kubernetes/sig-contributor-experience-misc

[chenopis]

@spiffxp Thanks for the heads up.

[spiffxp]

The above linked PR's are all of the offending repos currently munged by mungegithub, except for gengo which is vendored into kops.

This leaves mostly top-level and vendored OWNERS files for other kubernetes repos:

autoscaler/addon-resizer/vendor/k8s.io/kubernetes/pkg/api/OWNERS
autoscaler/addon-resizer/vendor/k8s.io/kubernetes/pkg/conversion/OWNERS
autoscaler/addon-resizer/vendor/k8s.io/kubernetes/pkg/runtime/OWNERS
dns/OWNERS
dns/vendor/k8s.io/kubernetes/pkg/api/OWNERS
dns/vendor/k8s.io/kubernetes/pkg/conversion/OWNERS
dns/vendor/k8s.io/kubernetes/pkg/runtime/OWNERS
features/OWNERS
frakti/OWNERS
ingress/OWNERS
k8s.io/OWNERS
kubeadm/OWNERS
kubectl/OWNERS
kubernetes-template-project/OWNERS
md-check/OWNERS
node-problem-detector/vendor/k8s.io/client-go/1.4/pkg/api/OWNERS
node-problem-detector/vendor/k8s.io/client-go/1.4/pkg/conversion/OWNERS
node-problem-detector/vendor/k8s.io/client-go/1.4/pkg/runtime/OWNERS
node-problem-detector/vendor/k8s.io/kubernetes/pkg/api/OWNERS
node-problem-detector/vendor/k8s.io/kubernetes/pkg/conversion/OWNERS
node-problem-detector/vendor/k8s.io/kubernetes/pkg/runtime/OWNERS
node-problem-detector/vendor/k8s.io/kubernetes/plugin/pkg/client/auth/oidc/OWNERS
perf-tests/network/vendor/k8s.io/client-go/pkg/conversion/OWNERS
perf-tests/network/vendor/k8s.io/client-go/pkg/runtime/OWNERS
perf-tests/network/vendor/k8s.io/client-go/plugin/pkg/client/auth/gcp/OWNERS
perf-tests/network/vendor/k8s.io/client-go/plugin/pkg/client/auth/oidc/OWNERS
perf-tests/OWNERS

What's the right thing to do for the vendored files? ref: https://github.com/kubernetes/test-infra/issues/3694

[spiffxp]

Going to ignore vendored OWNERS files, and opt to modify mungegithub to (selectively?) ignore them

[spiffxp]

Opened PR's to get rid of this in all of the other kubernetes repos, and picked up a few that popped back up in kubernetes/website

[spiffxp]

And that's all the kubernetes-incubator repos I could find that used assignees.

Let's see how long it takes for all these to merge

[spiffxp]

And that's all of them merged, can now remove the code that parses this field