fixed a typo

Author: ba1ajinaidu

content/en/docs/reference/setup-tools/kubeadm/kubeadm-upgrade.md

@@ -15,7 +15,7 @@ behind one command, with support for both planning an upgrade and actually perfo
 
 ## kubeadm upgrade guidance
 
-The steps for performing a upgrade using kubeadm are outlined in [this document](/docs/tasks/administer-cluster/kubeadm/kubeadm-upgrade/).
+The steps for performing an upgrade using kubeadm are outlined in [this document](/docs/tasks/administer-cluster/kubeadm/kubeadm-upgrade/).
 For older versions of kubeadm, please refer to older documentation sets of the Kubernetes website.
 
 You can use `kubeadm upgrade diff` to see the changes that would be applied to static pod manifests.