t4029: use sh instead of bash

Signed-off-by: Nguyễn Thái Ngọc Duy <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pclouds

t/t4029-diff-trailing-space.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 #
 # Copyright (c) Jim Meyering
 #