fix-scripts: specifically target bash over POSIX

backend/fix-scripts/001-fix_download_permissions.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 # INTERACTIVE PERMISSIONS FIX SCRIPT FOR YTDL-M
 # Date: 2022-05-03

backend/fix-scripts/002-fix_dupes_per_archive_file.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 # INTERACTIVE ARCHIVE-DUPE-ENTRY FIX SCRIPT FOR YTDL-M
 # Date: 2022-05-09