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/io/logger.go

@@ -21,7 +21,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"time"
 
 	"github.com/sirupsen/logrus"
@@ -43,7 +42,7 @@ const (
 
 // NewDiscardLogger creates logger which discards all the input.
 func NewDiscardLogger() io.WriteCloser {
-	return cioutil.NewNopWriteCloser(ioutil.Discard)
+	return cioutil.NewNopWriteCloser(io.Discard)
 }
 
 // NewCRILogger returns a write closer which redirect container log into

pkg/cri/io/logger_test.go

@@ -18,7 +18,7 @@ package io
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"strings"
 	"testing"
 	"time"
@@ -237,7 +237,7 @@ func TestRedirectLogs(t *testing.T) {
 		},
 	} {
 		t.Logf("TestCase %q", desc)
-		rc := ioutil.NopCloser(strings.NewReader(test.input))
+		rc := io.NopCloser(strings.NewReader(test.input))
 		buf := bytes.NewBuffer(nil)
 		wc := cioutil.NewNopWriteCloser(buf)
 		redirectLogs("test-path", rc, wc, test.stream, test.maxLen)