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>

oci/utils_unix.go

@@ -20,7 +20,6 @@
 package oci
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -53,7 +52,7 @@ func getDevices(path, containerPath string) ([]specs.LinuxDevice, error) {
 		return []specs.LinuxDevice{*dev}, nil
 	}
 
-	files, err := ioutil.ReadDir(path)
+	files, err := os.ReadDir(path)
 	if err != nil {
 		return nil, err
 	}