add notes for that strategic merge patch is unsupported for Custom Resource objects

Signed-off-by: pacoxu <[email protected]>
Co-authored-by: Tim Bannister <[email protected]>

Author: pacoxu

content/en/docs/tasks/manage-kubernetes-objects/update-api-object-kubectl-patch.md

@@ -445,6 +445,9 @@ and
 [kubectl apply](/docs/reference/generated/kubectl/kubectl-commands/#apply).
 
 
+{{< note >}}
+Strategic merge patch is not supported for custom resources.
+{{< /note >}}
 
 
 ## {{% heading "whatsnext" %}}