Update doc to generalise container runtime

What does this MR do?

CRI-O is used with Openshift and other Kubernetes distributions, however, it is not defacto for Kubernetes in general.

This change updates a note in the docs to generalise the reference to container runtimes.

GKE, for example, uses containerd by default:

❯ kubectl get node -o wide
NAME                     STATUS   ROLES    AGE   VERSION           INTERNAL-IP   EXTERNAL-IP   OS-IMAGE                             KERNEL-VERSION   CONTAINER-RUNTIME
gke-xxxx-7kd7            Ready    <none>   2d    v1.25.8-gke.500   10.10.0.4     xx.xx.xx.xx   Container-Optimized OS from Google   5.15.89+         containerd://1.6.18

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