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>

routers/web/repo/editor.go

@@ -6,7 +6,7 @@ package repo
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"path"
 	"strings"
@@ -127,7 +127,7 @@ func editFile(ctx *context.Context, isNewFile bool) {
 			return
 		}
 
-		d, _ := ioutil.ReadAll(dataRc)
+		d, _ := io.ReadAll(dataRc)
 		if err := dataRc.Close(); err != nil {
 			log.Error("Error whilst closing blob data: %v", err)
 		}