all: replace uses of ioutil with io and os (#24869)

les/api_test.go

@@ -20,7 +20,6 @@ import (
 	"context"
 	"errors"
 	"flag"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"sync"
@@ -423,7 +422,7 @@ func NewAdapter(adapterType string, services adapters.LifecycleConstructors) (ad
 		//	case "socket":
 		//		adapter = adapters.NewSocketAdapter(services)
 	case "exec":
-		baseDir, err0 := ioutil.TempDir("", "les-test")
+		baseDir, err0 := os.MkdirTemp("", "les-test")
 		if err0 != nil {
 			return nil, teardown, err0
 		}