refactor: move from io/ioutil to io and os packages (#5266)

The io/ioutil package has been deprecated as of Go 1.16 [1]. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.

[1]: https://golang.org/doc/go1.16#ioutil
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

pkg/simple/client/openpitrix/helmrepoindex/repo_index.go

@@ -24,7 +24,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"strings"
 	"time"
 
@@ -275,7 +274,7 @@ func ByteArrayToSavedIndex(data []byte) (*SavedIndex, error) {
 		return nil, err
 	}
 	r.Close()
-	b, err := ioutil.ReadAll(r)
+	b, err := io.ReadAll(r)
 
 	if err != nil && err != io.EOF {
 		return nil, err

pkg/simple/client/openpitrix/helmwrapper/helm_wrapper_test.go

@@ -17,7 +17,6 @@ limitations under the License.
 package helmwrapper
 
 import (
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -42,7 +41,7 @@ func TestHelmInstall(t *testing.T) {
 
 func TempDir(t *testing.T) string {
 	t.Helper()
-	d, err := ioutil.TempDir("", "kubesphere")
+	d, err := os.MkdirTemp("", "kubesphere")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -66,7 +65,7 @@ func GenerateChartData(t *testing.T, name string) string {
 	if err != nil {
 		t.Fatalf("Error creating chart for test: %v", err)
 	}
-	charData, err := ioutil.ReadFile(filename)
+	charData, err := os.ReadFile(filename)
 	if err != nil {
 		t.Fatalf("Error loading chart data %v", err)
 	}