Handle ioutil deprecations (#53526)

* replace ioutil.ReadFile -> os.ReadFile

* replace ioutil.ReadAll -> io.ReadAll

* replace ioutil.TempFile -> os.CreateTemp

* replace ioutil.NopCloser -> io.NopCloser

* replace ioutil.WriteFile -> os.WriteFile

* replace ioutil.TempDir -> os.MkdirTemp

* replace ioutil.Discard -> io.Discard

pkg/tsdb/cloudmonitoring/resource_handler_test.go

@@ -4,7 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -78,7 +78,7 @@ func Test_doRequest(t *testing.T) {
 		t.Errorf("Unexpected headers: %v", res.Header())
 	}
 	result := rw.Result()
-	body, err := ioutil.ReadAll(result.Body)
+	body, err := io.ReadAll(result.Body)
 	if err != nil {
 		t.Error(err)
 	}