Update cluster config for Windows & containerd GA

Update two references to change callout of preview state of containerd -> GA state.

Author: cwilhit

articles/aks/cluster-configuration.md

@@ -18,7 +18,7 @@ AKS supports Ubuntu 18.04 as the default node operating system (OS) in general a
 
 ## Container runtime configuration
 
-A container runtime is software that executes containers and manages container images on a node. The runtime helps abstract away sys-calls or operating system (OS) specific functionality to run containers on Linux or Windows. For Linux node pools, `containerd` is used for node pools using Kubernetes version 1.19 and greater. For Windows Server 2019 node pools, `containerd` is available in preview and can be used in node pools using Kubernetes 1.20 and greater, but Docker is still used by default.
+A container runtime is software that executes containers and manages container images on a node. The runtime helps abstract away sys-calls or operating system (OS) specific functionality to run containers on Linux or Windows. For Linux node pools, `containerd` is used for node pools using Kubernetes version 1.19 and greater. For Windows Server 2019 node pools, `containerd` is generally available and can be used in node pools using Kubernetes 1.20 and greater, but Docker is still used by default.
 
 [`Containerd`](https://containerd.io/) is an [OCI](https://opencontainers.org/) (Open Container Initiative) compliant core container runtime that provides the minimum set of required functionality to execute containers and manage images on a node. It was [donated](https://www.cncf.io/announcement/2017/03/29/containerd-joins-cloud-native-computing-foundation/) to the Cloud Native Compute Foundation (CNCF) in March of 2017. The current Moby (upstream Docker) version that AKS uses already leverages and is built on top of `containerd`, as shown above.
 
@@ -33,7 +33,7 @@ By using `containerd` for AKS nodes, pod startup latency improves and node resou
 > [!IMPORTANT]
 > Clusters with Linux node pools created on Kubernetes v1.19 or greater default to `containerd` for its container runtime. Clusters with node pools on a earlier supported Kubernetes versions receive Docker for their container runtime. Linux node pools will be updated to `containerd` once the node pool Kubernetes version is updated to a version that supports `containerd`. You can still use Docker node pools and clusters on older supported versions until those fall off support.
 > 
-> Using `containerd` with Windows Server 2019 node pools is currently in preview. For more details, see [Add a Windows Server node pool with `containerd`][aks-add-np-containerd].
+> Using `containerd` with Windows Server 2019 node pools is generally available, although the default for node pools created on Kubernetes v1.22 and earlier is still Docker. For more details, see [Add a Windows Server node pool with `containerd`][aks-add-np-containerd].
 > 
 > It is highly recommended to test your workloads on AKS node pools with `containerd` prior to using clusters with a Kubernetes version that supports `containerd` for your node pools.