change the csi-test import path to v4

Author: fengzixu

Diff for: prow.sh

@@ -228,7 +228,7 @@ configvar CSI_PROW_E2E_IMPORT_PATH "k8s.io/kubernetes" "E2E package"
 # and install it inside the cluster, which is not necessarily easier.
 configvar CSI_PROW_SANITY_REPO https://github.com/kubernetes-csi/csi-test "csi-test repo"
 configvar CSI_PROW_SANITY_VERSION af2d21f66c88d7b4956c17d8123cdc563ca0ba0a "csi-test version" # latest master
-configvar CSI_PROW_SANITY_IMPORT_PATH github.com/kubernetes-csi/csi-test "csi-test package"
+configvar CSI_PROW_SANITY_IMPORT_PATH github.com/kubernetes-csi/csi-test/v4 "csi-test package"
 configvar CSI_PROW_SANITY_SERVICE "hostpath-service" "Kubernetes TCP service name that exposes csi.sock"
 configvar CSI_PROW_SANITY_POD "csi-hostpathplugin-0" "Kubernetes pod with CSI driver"
 configvar CSI_PROW_SANITY_CONTAINER "hostpath" "Kubernetes container with CSI driver"