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/csv/csv.go

@@ -9,7 +9,6 @@ import (
 	"bytes"
 	"html"
 	"io"
-	"io/ioutil"
 	"regexp"
 	"strconv"
 
@@ -87,7 +86,7 @@ func (Renderer) Render(ctx *markup.RenderContext, input io.Reader, output io.Wri
 	var tmpBlock = bufio.NewWriter(output)
 
 	// FIXME: don't read all to memory
-	rawBytes, err := ioutil.ReadAll(input)
+	rawBytes, err := io.ReadAll(input)
 	if err != nil {
 		return err
 	}