* Plugins

      * Introduces the ability to extend kubectl by adding third-party plugins. Developer preview, please refer to the documentation for instructions about how to use it. ([#37499](https://github.com/kubernetes/kubernetes/pull/37499), [@fabianofranz](https://github.com/fabianofranz))

* v1.Pod now has a field to configure whether a single process namespace should be shared between all containers in a pod. This feature is in alpha preview. ([#58716](https://github.com/kubernetes/kubernetes/pull/58716), [@verb](https://github.com/verb))

* Added golint check for pkg/kubelet. ([#47316](https://github.com/kubernetes/kubernetes/pull/47316), [@k82cn](https://github.com/k82cn))
* azure: acr: support MSI with preview ACR with AAD auth ([#48981](https://github.com/kubernetes/kubernetes/pull/48981), [@colemickens](https://github.com/colemickens))

*   Azure NSG rules can be consolidated to reduce the likelihood of hitting Azure resource limits (available only in regions where the Augmented Security Groups preview is available).  ([#55740](https://github.com/kubernetes/kubernetes/pull/55740), [@itowlson](https://github.com/itowlson))

    - `kubectl create clusterrolebinding anonymous-discovery --clusterrole=system:discovery --group=system:unauthenticated`
    - `kubectl create clusterrolebinding anonymous-access-review --clusterrole=system:basic-user --group=system:unauthenticated`

- Renames the timeout field for the DelegatingAuthenticationOptions to TokenRequestTimeout and set the timeout only for the token review client. Previously the timeout was also applied to watches making them reconnecting every 10 seconds. ([#101102](https://github.com/kubernetes/kubernetes/pull/101102), [@p0lyn0mial](https://github.com/p0lyn0mial)) [SIG API Machinery, Auth and Cloud...

- Renames the timeout field for the `DelegatingAuthenticationOptions` to `TokenRequestTimeout` and set the timeout only for the token review client. Previously the timeout was also applied to watches making them reconnecting every 10 seconds. ([#100959](https://github.com/kubernetes/kubernetes/pull/100959), [@p0lyn0mial](https://github.com/p0lyn0mial))

- Renames the timeout field for the DelegatingAuthenticationOptions to TokenRequestTimeout and set the timeout only for the token review client. Previously the timeout was also applied to watches making them reconnecting every 10 seconds. ([#101103](https://github.com/kubernetes/kubernetes/pull/101103), [@p0lyn0mial](https://github.com/p0lyn0mial)) [SIG API Machinery, Auth and Cloud...