Update shebangs

install.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 echo "Copying Systemd units to system directory..."
 sudo cp systemd-templates/dns-update.service /etc/systemd/system/

main.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 source "$(dirname "$0")/variables.conf"
 

variables.conf.template

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # Copy this file as variables.conf, with the correct values