fix: kubernetes design proposal URL expired

Because of Kubernetes proposal design proposals have been archived, the
relevant link in the current document is no longer working. So I made an
update with this commit.

Signed-off-by: LetFu <[email protected]>

Author: LetFu

Diff for: README.md

@@ -3,7 +3,7 @@
 The external-provisioner is a sidecar container that dynamically provisions volumes by calling `CreateVolume` and `DeleteVolume` functions of CSI drivers. It is necessary because internal persistent volume controller running in Kubernetes controller-manager does not have any direct interfaces to CSI drivers.
 
 ## Overview
-The external-provisioner is an external controller that monitors `PersistentVolumeClaim` objects created by user and creates/deletes volumes for them. Full design can be found at Kubernetes proposal at [container-storage-interface.md](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/storage/container-storage-interface.md)
+The external-provisioner is an external controller that monitors `PersistentVolumeClaim` objects created by user and creates/deletes volumes for them. Full design can be found at Kubernetes proposal at [container-storage-interface.md](https://github.com/kubernetes/design-proposals-archive/blob/main/storage/container-storage-interface.md)
 
 ## Compatibility
 
@@ -132,7 +132,7 @@ See the [storage capacity section](#capacity-support) below for details.
 
 External-provisioner interacts with Kubernetes by watching PVCs and
 PVs and implementing the [external provisioner
-protocol](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/storage/container-storage-interface.md#provisioning-and-deleting).
+protocol](https://github.com/kubernetes/design-proposals-archive/blob/main/storage/container-storage-interface.md#provisioning-and-deleting).
 The [design document](./doc/design.md) explains this in more detail.
 
 ### Topology support

Diff for: doc/design.md

@@ -2,7 +2,7 @@
 
 External-provisioner interacts with Kubernetes by watching PVCs and
 PVs and implementing the [external provisioner
-protocol](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/storage/container-storage-interface.md#provisioning-and-deleting).
+protocol](https://github.com/kubernetes/design-proposals-archive/blob/main/storage/container-storage-interface.md#provisioning-and-deleting).
 The following diagram illustrates that, starting with the creation of
 a PVC by a user and ending with the removal of all resources.