Us sigs.k8s.io/yaml over github.com/ghodss/yaml

[acpana]

From a PR discussion, we should use what k8s uses for interacting with yaml. The PR referenced below actually shows the "trick" to migrating to the k8s lib.

Also it would be swell to turn on the import linter in the golanci-lint tool to prevent such imports in the future.

Originally posted by @justinsb in #3435 (comment)