Bump NodeProblemDetector version to v0.8.0 to reduce forced NodeStatus updates frequency to 5 minutes. ([#84007](https://github.com/kubernetes/kubernetes/pull/84007), [@wojtek-t](https://github.com/wojtek-t))

- `apidiscovery.k8s.io/v2beta1` API group is disabled by default ([#130347](https://github.com/kubernetes/kubernetes/pull/130347), [@Jefftree](https://github.com/Jefftree)) [SIG API Machinery and Testing]
- `kubectl apply` now coerces `null` values for labels and annotations in manifests to empty string values, 

- Scheduler alpha metrics binding_duration_seconds and scheduling_algorithm_preemption_evaluation_seconds are deprecated, Both of those metrics are now covered as part of framework_extension_point_duration_seconds, the former as a PostFilter the latter and a Bind plugin. The plan is to remove both in 1.21 ([#95001](https://github.com/kubernetes/kubernetes/pull/95001), [@arghya88](https://github.com/arghya88))...

- The PodDisruptionBudget `spec.unhealthyPodEvictionPolicy` field has graduated to beta and is enabled by default. On servers with the feature enabled, this field may be set to `AlwaysAllow` to always allow unhealthy pods covered by the PodDisruptionBudget to be evicted. ([#115363](https://github.com/kubernetes/kubernetes/pull/115363), [@ravisantoshgudimetla](https://github.com/ravisantoshgudimetla)) [SIG Apps, Auth and Node]

- The PodDisruptionBudget `spec.unhealthyPodEvictionPolicy` field has graduated to GA. This field may be set to `AlwaysAllow` to always allow unhealthy pods covered by the PodDisruptionBudget to be evicted. ([#123428](https://github.com/kubernetes/kubernetes/pull/123428), [@atiratree](https://github.com/atiratree)) [SIG Apps, Auth, Node and Testing]

these files before upgrading.** When specifying keys in JSON resource definitions during direct API server communication, the keys are case-sensitive. A bug introduced in Kubernetes 1.8 caused the API server to accept a request with incorrect case and coerce it to correct case, but this behaviour has been fixed in 1.11 and the API server will once again be enforcing the correct case. It’s worth noting that during this time, the `kubectl` tool continued to enforce case-sensitive keys, so users that strictly...

protobuf/etcd3 switch, and any changes since the backup will be lost.  As 1.5
does not support protobuf encoding, if you roll back to 1.5 after upgrading to
protobuf you will be forced to restore from backup, and you will lose any changes
since you converted to protobuf.  After conversion to protobuf, you should
validate the correct operation of your cluster thoroughly before returning it
to normal operation.