io/ioutil has already been deprecated in golang 1.16, so replace all ioutil with io and os

test/e2e/e2e.go

@@ -20,7 +20,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path"
@@ -298,7 +297,7 @@ func logClusterImageSources() {
 
 	outputBytes, _ := json.MarshalIndent(images, "", "  ")
 	filePath := filepath.Join(framework.TestContext.ReportDir, "images.json")
-	if err := ioutil.WriteFile(filePath, outputBytes, 0644); err != nil {
+	if err := os.WriteFile(filePath, outputBytes, 0644); err != nil {
 		framework.Logf("cluster images sources, could not write to %q: %v", filePath, err)
 	}
 }