*: remove io/ioutil uses

Close #1764.

scripts/compare-dumps/compare-dumps.go

@@ -7,7 +7,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -32,7 +31,7 @@ type storageOp struct {
 }
 
 func readFile(path string) (dump, error) {
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}