fix linter issue

Author: paulyufan2

cni/network/invoker_cns_test.go

@@ -326,7 +326,7 @@ func TestCNSIPAMInvoker_Add_Overlay(t *testing.T) {
 						Gateway: net.ParseIP("10.0.0.1"),
 					},
 				},
-				Routes:            ([]network.RouteInfo)(nil),
+				Routes:            []network.RouteInfo(nil),
 				NICType:           cns.InfraNIC,
 				SkipDefaultRoutes: true,
 				HostSubnetPrefix:  *parseCIDR("10.0.0.0/24"),
@@ -1716,7 +1716,7 @@ func TestCNSIPAMInvoker_Add_SwiftV2(t *testing.T) {
 						Gateway: net.ParseIP("10.0.0.1"),
 					},
 				},
-				Routes:            ([]network.RouteInfo)(nil),
+				Routes:            []network.RouteInfo(nil),
 				NICType:           cns.InfraNIC,
 				SkipDefaultRoutes: true,
 				HostSubnetPrefix:  *parseCIDR("10.0.0.0/24"),
@@ -1739,7 +1739,7 @@ func TestCNSIPAMInvoker_Add_SwiftV2(t *testing.T) {
 					NICType:    cns.BackendNIC,
 					MacAddress: ibParsedMacAddress,
 					PnPID:      pnpID,
-					Routes:     ([]network.RouteInfo)(nil),
+					Routes:     []network.RouteInfo(nil),
 				},
 			},
 			wantErr: false,