Clarify how to set a cluster as single-stack

Signed-off-by: Bridget Kromhout <[email protected]>

Author: bridgetkromhout

keps/sig-network/563-dual-stack/README.md

@@ -1392,8 +1392,8 @@ This capability will move to stable when the following criteria have been met.
 * **How can this feature be enabled / disabled in a live cluster?**
   - With this feature moving to stable, the feature will always be enabled.
   - While disabling the feature is not possible, using it is not required. Any
-    cluster can be provisioned with the `spec.ipFamilyPolicy` field set to
-    `SingleStack`.
+    cluster can be provisioned as single-stack by setting `--cluster-cidr` to
+    only one CIDR and ` --service-cluster-ip-range` to only one address block.
 
 * **Does enabling the feature change any default behavior?**
   Pods and Services will remain single-stack until cli flags have been modified

keps/sig-network/563-dual-stack/kep.yaml

@@ -19,7 +19,7 @@ prr-approvers:
   - "@johnbelamaric"
 editor: TBD
 creation-date: "2018-05-21"
-last-updated: "2021-04-23"
+last-updated: "2021-04-26"
 status: implemented
 stage: stable
 latest-milestone: v1.22