Replace usages of ioutil.ReadDir

This changes the return type to []fs.DirEntry. However, as we only use
the filenames anyways, this doesn't make a difference.

cmd/restic/integration_helpers_unix_test.go

@@ -6,7 +6,6 @@ package main
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -57,7 +56,7 @@ func nlink(info os.FileInfo) uint64 {
 func createFileSetPerHardlink(dir string) map[uint64][]string {
 	var stat syscall.Stat_t
 	linkTests := make(map[uint64][]string)
-	files, err := ioutil.ReadDir(dir)
+	files, err := os.ReadDir(dir)
 	if err != nil {
 		return nil
 	}

cmd/restic/integration_helpers_windows_test.go

@@ -6,7 +6,6 @@ package main
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 )
 
@@ -39,7 +38,7 @@ func inode(info os.FileInfo) uint64 {
 
 func createFileSetPerHardlink(dir string) map[uint64][]string {
 	linkTests := make(map[uint64][]string)
-	files, err := ioutil.ReadDir(dir)
+	files, err := os.ReadDir(dir)
 	if err != nil {
 		return nil
 	}

helpers/prepare-release/main.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -366,7 +365,7 @@ func runBuild(sourceDir, outputDir, version string) {
 }
 
 func readdir(dir string) []string {
-	fis, err := ioutil.ReadDir(dir)
+	fis, err := os.ReadDir(dir)
 	if err != nil {
 		die("readdir %v failed: %v", dir, err)
 	}