chore: Drop deprecated io/ioutil

Signed-off-by: shuheiktgw <shuheiktgw@users.noreply.github.com>

pkg/controller/scheduler_daemonset_test.go

@@ -20,7 +20,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -445,7 +445,7 @@ func TestScheduler_DaemonSetTargetPortName(t *testing.T) {
 
 func TestScheduler_DaemonSetAlerts(t *testing.T) {
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		b, err := ioutil.ReadAll(r.Body)
+		b, err := io.ReadAll(r.Body)
 		require.NoError(t, err)
 		var payload = notifier.SlackPayload{}
 		err = json.Unmarshal(b, &payload)

pkg/controller/scheduler_deployment_test.go

@@ -20,7 +20,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -596,7 +596,7 @@ func TestScheduler_DeploymentTargetPortName(t *testing.T) {
 
 func TestScheduler_DeploymentAlerts(t *testing.T) {
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		b, err := ioutil.ReadAll(r.Body)
+		b, err := io.ReadAll(r.Body)
 		require.NoError(t, err)
 		var payload = notifier.SlackPayload{}
 		err = json.Unmarshal(b, &payload)

pkg/controller/webhook.go

@@ -22,7 +22,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -67,7 +67,7 @@ func callWebhook(webhook string, payload interface{}, timeout string) error {
 	}
 	defer r.Body.Close()
 
-	b, err := ioutil.ReadAll(r.Body)
+	b, err := io.ReadAll(r.Body)
 	if err != nil {
 		return fmt.Errorf("error reading body: %s", err.Error())
 	}