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/fuzz/container_fuzzer.go

@@ -27,7 +27,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"strings"
@@ -148,7 +147,7 @@ func checkIfShouldRestart(err error) {
 // startDaemon() starts the daemon.
 func startDaemon(ctx context.Context, shouldTearDown bool) {
 	buf := bytes.NewBuffer(nil)
-	stdioFile, err := ioutil.TempFile("", "")
+	stdioFile, err := os.CreateTemp("", "")
 	if err != nil {
 		// We panic here as it is a fuzz-blocker that
 		// may need fixing