[code-quality] More portable shebangs (#7189)

Co-authored-by: Keith Burzinski <kbx81x@gmail.com>

docker/docker_entrypoint.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # If /cache is mounted, use that as PIO's coredir
 # otherwise use path in /config (so that PIO packages aren't downloaded on each compile)

script/devcontainer-post-create

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -e
 # set -x

script/quicklint

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -e
 

script/setup

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Set up ESPHome dev environment
 
 set -e