refactor: move from io/ioutil to io and os package (#17109)

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>

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

modules/markup/external/external.go

@@ -8,7 +8,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"runtime"
@@ -75,7 +74,7 @@ func (p *Renderer) Render(ctx *markup.RenderContext, input io.Reader, output io.
 
 	if p.IsInputFile {
 		// write to temp file
-		f, err := ioutil.TempFile("", "gitea_input")
+		f, err := os.CreateTemp("", "gitea_input")
 		if err != nil {
 			return fmt.Errorf("%s create temp file when rendering %s failed: %v", p.Name(), p.Command, err)
 		}