refactor: move from io/ioutil to io and os package

The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

pkg/cri/server/helpers_linux_test.go

@@ -17,7 +17,6 @@
 package server
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -66,11 +65,11 @@ func TestEnsureRemoveAllWithMount(t *testing.T) {
 		t.Skip("skipping test that requires root")
 	}
 
-	dir1, err := ioutil.TempDir("", "test-ensure-removeall-with-dir1")
+	dir1, err := os.MkdirTemp("", "test-ensure-removeall-with-dir1")
 	if err != nil {
 		t.Fatal(err)
 	}
-	dir2, err := ioutil.TempDir("", "test-ensure-removeall-with-dir2")
+	dir2, err := os.MkdirTemp("", "test-ensure-removeall-with-dir2")
 	if err != nil {
 		t.Fatal(err)
 	}