Use bash for install script

Bug: b/221232298

Change-Id: I11733ebad2c6898fb1d199005ba8b6ec7e7dc77b

install_hooks.sh

diff --git a/install_hooks.sh b/install_hooks.sh
index 10463c4..c4c2287 100755
--- a/install_hooks.sh
+++ b/install_hooks.sh
@@ -1,4 +1,4 @@
-#! /usr/bin/env sh
+#! /usr/bin/env bash
 
 dir=`realpath $(dirname "$BASH_SOURCE:-0")`
 githookdir=`git rev-parse --git-dir`/hooks