fix(git): add vendor in .gitignore

vendor/golang.org/x/sys/unix/readdirent_getdents.go

@@ -1,13 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build aix || dragonfly || freebsd || linux || netbsd || openbsd
-// +build aix dragonfly freebsd linux netbsd openbsd
-
-package unix
-
-// ReadDirent reads directory entries from fd and writes them into buf.
-func ReadDirent(fd int, buf []byte) (n int, err error) {
-	return Getdents(fd, buf)
-}