`Initializers` admission plugin is enabled.([#51436](https://github.com/kubernetes/kubernetes/pull/51436))

* [Action required] The validation rule for metadata.initializers.pending[x].name is tightened. The initializer name must contain at least three segments, separated by dots. You can create objects with pending initializers and not rely on the API server to add pending initializers according to `initializerConfiguration`. If you do so, update the initializer name in the existing objects and...

  
  Changed `kubectl create secret --help` description. There will be a short introduction to the three secret types and clearer guidance on how to use the command. ([#117930](https://github.com/kubernetes/kubernetes/pull/117930), [@LronDC](https://github.com/LronDC))