fixed broken links on design dir

Signed-off-by: SafeEHA <[email protected]>

design/baremetal-operator/kubebuilder-migration.md

@@ -215,7 +215,7 @@ all metal3 repositories.
 - The [v1alpha2 API
  migration](https://github.com/metal3-io/metal3-docs/pull/101)
  proposal.
-- [operator-sdk 1.0 migration guide](https://sdk.operatorframework.io/docs/building-operators/golang/project_migration_guide/)
+- [operator-sdk 1.0 migration guide](https://sdk.operatorframework.io/docs/building-operators/golang/migration/)
 - [migration implementation pull request](https://github.com/metal3-io/baremetal-operator/pull/655)
 - updates to kustomize deployment files and CI fixes:
  - <https://github.com/metal3-io/baremetal-operator/pull/672>

design/nodes-machines-and-hosts.md

@@ -57,7 +57,7 @@ such as draining the node for maintenance. The definition of Node is
 owned by the Kubernetes core, and offers few opportunities to attach
 custom data.
 
-[Machine](https://kubernetes-sigs.github.io/cluster-api/common_code/machine_controller.html)
+[Machine](https://cluster-api.sigs.k8s.io/developer/architecture/controllers/machine)
 objects represent a *request* for an instance of kubelet. A parallel
 design is the persistent volume claim and persistent volume in the
 storage APIs. The Machine CRD is owned by the cluster-api SIG. Machine

design/sync-labels-bmh-to-node.md

@@ -244,7 +244,7 @@ this label.
 
 There is also a security vulnerability associated with kubelet's ability to
 self-label the Node object. This has been
-[addressed](https://github.com/kubernetes/enhancements/blob/master/keps/sig-auth/0000-20170814-bounding-self-labeling-kubelets.md).
+[addressed](https://github.com/kubernetes/enhancements/blob/master/keps/sig-auth/279-limit-node-access/README.md).
 However, as a consequence, BMH labels that fall within the *.kubernetes.io/*
 space cannot be specified via kubelet's `--node-labels` flag.