Merge pull request #646 from hidekazuna/exdoc

📖 Update external cloud provider URL

Author: k8s-ci-robot

docs/external-cloud-provider.md

@@ -1,6 +1,6 @@
 # External Cloud Provider
 
-To deploy a cluster using [external cloud provider](https://github.com/kubernetes-sigs/cloud-provider-openstack), create a cluster configuration with the [external cloud provider template](../templates/cluster-template-external-cloud-provider.yaml).
+To deploy a cluster using [external cloud provider](https://github.com/kubernetes/cloud-provider-openstack), create a cluster configuration with the [external cloud provider template](../templates/cluster-template-external-cloud-provider.yaml).
 
 ## Steps