Update csi-sanity test suite to v4.3.0

Allows for testing of the SINGLE_NODE_MULTI_WRITER capability.

prow.sh

@@ -234,7 +234,7 @@ configvar CSI_PROW_E2E_IMPORT_PATH "k8s.io/kubernetes" "E2E package"
 # of the cluster. The alternative would have been to (cross-)compile csi-sanity
 # 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 v4.2.0 "csi-test version"
+configvar CSI_PROW_SANITY_VERSION v4.3.0 "csi-test version"
 configvar CSI_PROW_SANITY_PACKAGE_PATH github.com/kubernetes-csi/csi-test "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"