Update controller-manager-leader-migration.md

The example of `LeaderMigrationConfiguration` is missing the `resourceLock`, which is required according to the documentation. [1]

[1] https://kubernetes.io/docs/reference/config-api/kube-controller-manager-config.v1alpha1/#controllermanager-config-k8s-io-v1alpha1-LeaderMigrationConfiguration

content/en/docs/tasks/administer-cluster/controller-manager-leader-migration.md

@@ -105,6 +105,7 @@ Leader Migration can be enabled without a configuration. Please see
 kind: LeaderMigrationConfiguration
 apiVersion: controllermanager.config.k8s.io/v1
 leaderName: cloud-provider-extraction-migration
+resourceLock: leases
 controllerLeaders:
   - name: route
     component: kube-controller-manager
@@ -123,6 +124,7 @@ between both parties of the migration.
 kind: LeaderMigrationConfiguration
 apiVersion: controllermanager.config.k8s.io/v1
 leaderName: cloud-provider-extraction-migration
+resourceLock: leases
 controllerLeaders:
   - name: route
     component: *
@@ -156,6 +158,7 @@ which has the same effect.
 kind: LeaderMigrationConfiguration
 apiVersion: controllermanager.config.k8s.io/v1
 leaderName: cloud-provider-extraction-migration
+resourceLock: leases
 controllerLeaders:
   - name: route
     component: cloud-controller-manager
@@ -235,6 +238,7 @@ controllers.
 kind: LeaderMigrationConfiguration
 apiVersion: controllermanager.config.k8s.io/v1
 leaderName: cloud-provider-extraction-migration
+resourceLock: leases
 controllerLeaders:
   - name: route
     component: *