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/log/conn_test.go

@@ -6,7 +6,7 @@ package log
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"strings"
 	"sync"
@@ -20,7 +20,7 @@ func listenReadAndClose(t *testing.T, l net.Listener, expected string) {
 	conn, err := l.Accept()
 	assert.NoError(t, err)
 	defer conn.Close()
-	written, err := ioutil.ReadAll(conn)
+	written, err := io.ReadAll(conn)
 
 	assert.NoError(t, err)
 	assert.Equal(t, expected, string(written))