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/devops/jenkins/jenkins.go

@@ -20,7 +20,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"net/url"
@@ -849,7 +848,7 @@ func (j *Jenkins) CheckCron(projectName string, httpParameters *devops.HttpParam
 
 	reader = httpParameters.Body
 	//nolint:ineffassign,staticcheck
-	cronData, err := ioutil.ReadAll(reader)
+	cronData, err := io.ReadAll(reader)
 	err = json.Unmarshal(cronData, cron)
 	if err != nil {
 		klog.Error(err)

pkg/simple/client/devops/jenkins/request.go

@@ -21,7 +21,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"mime/multipart"
 	"net/http"
 	"net/url"
@@ -185,7 +184,8 @@ func (r *Requester) SetClient(client *http.Client) *Requester {
 	return r
 }
 
-//Add auth on redirect if required.
+// Add auth on redirect if required.
+//
 //nolint:unused
 func (r *Requester) redirectPolicyFunc(req *http.Request, via []*http.Request) error {
 	if r.BasicAuth != nil {
@@ -448,7 +448,7 @@ func (r *Requester) DoPostForm(ar *APIRequest, responseStruct interface{}, form
 func (r *Requester) ReadRawResponse(response *http.Response, responseStruct interface{}) (*http.Response, error) {
 	defer response.Body.Close()
 
-	content, err := ioutil.ReadAll(response.Body)
+	content, err := io.ReadAll(response.Body)
 	if err != nil {
 		return nil, err
 	}
@@ -478,7 +478,7 @@ func CheckResponse(r *http.Response) error {
 	}
 	defer r.Body.Close()
 	errorResponse := &devops.ErrorResponse{Response: r}
-	data, err := ioutil.ReadAll(r.Body)
+	data, err := io.ReadAll(r.Body)
 	if err == nil && data != nil {
 		errorResponse.Body = data
 		errorResponse.Message = string(data)

pkg/simple/client/devops/jenkins/utils.go

@@ -18,7 +18,6 @@ import (
 	"compress/gzip"
 	"encoding/json"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/url"
 	"strings"
@@ -64,7 +63,7 @@ func getRespBody(resp *http.Response) ([]byte, error) {
 	} else {
 		reader = resp.Body
 	}
-	resBody, err := ioutil.ReadAll(reader)
+	resBody, err := io.ReadAll(reader)
 	if err != nil {
 		klog.Error(err)
 		return nil, err