fix url for 1.11 docs (kubernetes#10087)

The URL was not updated to point to release-1.11 branch when 1.11 was released.
This PR updates it to use the docsbranch param, so we don't have to
update it for every release.

content/en/docs/tasks/administer-cluster/kubelet-config-file.md

@@ -30,7 +30,7 @@ it simplifies node deployment and configuration management.
 
 The subset of the Kubelet's configuration that can be configured via a file
 is defined by the `KubeletConfiguration` struct
-[here (v1beta1)](https://github.com/kubernetes/kubernetes/blob/release-1.10/pkg/kubelet/apis/kubeletconfig/v1beta1/types.go).
+[here (v1beta1)](https://github.com/kubernetes/kubernetes/blob/{{< param "docsbranch" >}}/pkg/kubelet/apis/kubeletconfig/v1beta1/types.go).
 
 The configuration file must be a JSON or YAML representation of the parameters
 in this struct. Make sure the Kubelet has read permissions on the file.