Update dependencies

vendor/tailscale.com/clientupdate/clientupdate_downloads.go

@@ -0,0 +1,20 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build (linux && !android) || windows
+
+package clientupdate
+
+import (
+	"context"
+
+	"tailscale.com/clientupdate/distsign"
+)
+
+func (up *Updater) downloadURLToFile(pathSrc, fileDst string) (ret error) {
+	c, err := distsign.NewClient(up.Logf, up.PkgsAddr)
+	if err != nil {
+		return err
+	}
+	return c.Download(context.Background(), pathSrc, fileDst)
+}