docs: update containerd systemd configuration

systemd_cgroup = true in plugins."io.containerd.grpc.v1.cri" is no longer
supported by containerd 1.3.x. Enabling it causes containerd to skip loading
the cri plugin.

Add the preferred setting to the container runtime configuration documentation.

Ref: containerd/containerd#4574

Signed-off-by: Mikko Ylinen <[email protected]>

Author: mythi

content/en/docs/setup/production-environment/container-runtimes.md

@@ -472,11 +472,13 @@ Start-Service containerd
 
 ### systemd
 
-To use the `systemd` cgroup driver in `/etc/containerd/config.toml` set
+To use the `systemd` cgroup driver in `/etc/containerd/config.toml` with `runc` set
 
 ```
-[plugins.cri]
-systemd_cgroup = true
+[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
+  ...
+  [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
+    SystemdCgroup = true
 ```
 When using kubeadm, manually configure the
 [cgroup driver for kubelet](/docs/setup/production-environment/tools/kubeadm/install-kubeadm/#configure-cgroup-driver-used-by-kubelet-on-control-plane-node)