delete update-deps.sh

This script was used when a custom gitlock tool was used for package
management. That approach has been superseded with the switch to the
module mode, and gitlock was deleted in CL 176604. By now, there are
no directories with an update-deps make target remaining.

For golang/go#26872.

Change-Id: Ia7f5d9e8b277be55010d5752523d1160b72115b2
Reviewed-on: https://go-review.googlesource.com/c/build/+/227440
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Alexander Rakoczy <alex@golang.org>
Run-TryBot: Alexander Rakoczy <alex@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/update-deps.sh b/update-deps.sh
deleted file mode 100755
index 804c9a5..0000000
--- a/update-deps.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/bin/bash
-# Copyright 2017 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.
-
-# Run "make update-deps" in each directory with such a target.
-
-for x in $(git grep -l update-deps | grep Makefile); do (cd $(dirname $x) && make update-deps); done