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>

contrib/apparmor/apparmor.go

@@ -22,7 +22,6 @@ package apparmor
 import (
 	"bytes"
 	"context"
-	"io/ioutil"
 	"os"
 
 	"github.com/containerd/containerd/containers"
@@ -65,7 +64,7 @@ func LoadDefaultProfile(name string) error {
 	if err != nil {
 		return err
 	}
-	f, err := ioutil.TempFile(os.Getenv("XDG_RUNTIME_DIR"), p.Name)
+	f, err := os.CreateTemp(os.Getenv("XDG_RUNTIME_DIR"), p.Name)
 	if err != nil {
 		return err
 	}

contrib/apparmor/template.go

@@ -25,7 +25,6 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path"
 	"strconv"
@@ -131,7 +130,7 @@ func loadData(name string) (*data, error) {
 	p.Version = ver
 
 	// Figure out the daemon profile.
-	currentProfile, err := ioutil.ReadFile("/proc/self/attr/current")
+	currentProfile, err := os.ReadFile("/proc/self/attr/current")
 	if err != nil {
 		// If we couldn't get the daemon profile, assume we are running
 		// unconfined which is generally the default.