Fix links in the tasks section

This PR fixes links where the target is a redirection. The special case
is about minikube, which has been deleted recently. The dangling link
now points to `/docs/tasks/tools/` which makes no sense. This PR change
the target for `minikube` to `https://minikube.sigs.k8s.io/docs/`.

content/en/docs/tasks/administer-cluster/kubeadm/kubeadm-certs.md

@@ -10,7 +10,7 @@ weight: 10
 
 {{< feature-state for_k8s_version="v1.15" state="stable" >}}
 
-Client certificates generated by [kubeadm](/docs/reference/setup-tools/kubeadm/kubeadm/) expire after 1 year. This page explains how to manage certificate renewals with kubeadm.
+Client certificates generated by [kubeadm](/docs/reference/setup-tools/kubeadm/) expire after 1 year. This page explains how to manage certificate renewals with kubeadm.
 
 ## {{% heading "prerequisites" %}}
 

content/en/docs/tasks/administer-cluster/network-policy-provider/romana-network-policy.md

@@ -12,7 +12,7 @@ This page shows how to use Romana for NetworkPolicy.
 
 ## {{% heading "prerequisites" %}}
 
-Complete steps 1, 2, and 3 of the [kubeadm getting started guide](/docs/reference/setup-tools/kubeadm/kubeadm/).
+Complete steps 1, 2, and 3 of the [kubeadm getting started guide](/docs/reference/setup-tools/kubeadm/).
 
 <!-- steps -->
 

content/en/docs/tasks/administer-cluster/network-policy-provider/weave-network-policy.md

@@ -13,7 +13,7 @@ This page shows how to use Weave Net for NetworkPolicy.
 ## {{% heading "prerequisites" %}}
 
 You need to have a Kubernetes cluster. Follow the
-[kubeadm getting started guide](/docs/reference/setup-tools/kubeadm/kubeadm/) to bootstrap one.
+[kubeadm getting started guide](/docs/reference/setup-tools/kubeadm/) to bootstrap one.
 
 <!-- steps -->