fix `libcontainer/integration/exec_test.go:1859:8: undefined: ioutil`
Fix
@@ -1856,7 +1856,7 @@ func TestBindMountAndUser(t *testing.T) {
err := os.MkdirAll(dirhost, 0o755)
ok(t, err)
- err = ioutil.WriteFile(filepath.Join(dirhost, "foo.txt"), []byte("Hello"), 0o755)
+ err = os.WriteFile(filepath.Join(dirhost, "foo.txt"), []byte("Hello"), 0o755)
ok(t, err)
// Make this dir inaccessible to "group,others".
