Try and make zsh complain less

My turn to make "this cant possibly break" changes to the scripts.

scripts/apatch.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 gitcmd="git -c commit.gpgsign=false"
 

scripts/checkoutpr.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 if [ -z "$1" ]; then
 	echo "$0 <prID>"
 	exit 1;