Fixup: Add missing instruction for bootstrap

clusters/k8s01/bootstrap.yaml

+apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
+kind: Kustomization
+metadata:
+  name: bootstrap
+  namespace: flux-system
+spec:
+  interval: 10m0s
+  sourceRef:
+    kind: GitRepository
+    name: flux-system
+  path: ./bootstrap
+  prune: true
+  validation: client