Fixed the shebang on build_number.sh so that it works with debian-ish distros

require-ess/tools/build_number.sh

-#!/bin/env bash
+#!/usr/bin/env bash
 # Small script to fetch current build nuber for a given module. If you pass a numeric version
 # but no build number, it fetches the latest build number installed from the target e3 env.
 #