refactor: move from io/ioutil to io and os packages (#1546)

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>

core/streamState.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"time"
@@ -88,7 +87,7 @@ func SetStreamAsDisconnected() {
 
 	offlineFileData := static.GetOfflineSegment()
 	offlineFilename := "offline.ts"
-	offlineTmpFile, err := ioutil.TempFile(os.TempDir(), offlineFilename)
+	offlineTmpFile, err := os.CreateTemp(os.TempDir(), offlineFilename)
 	if err != nil {
 		log.Errorln("unable to create temp file for offline video segment")
 	}