Fixes #2508: Change into backup directory

This fix ensures that the backup-script will change into the backup directory before running.

Users backup via root user will no longer get a warning, that the script couldn't change into '/root'

contrib/backup/zammad_backup.sh

@@ -7,6 +7,9 @@ PATH=/sbin:/bin:/usr/sbin:/usr/bin:
 BACKUP_SCRIPT_PATH="$(dirname $(realpath $0))"
 
 if [ -f "${BACKUP_SCRIPT_PATH}/config" ]; then
+  # Ensure we're inside of our Backup-Script folder (see issue 2508)
+  cd "${BACKUP_SCRIPT_PATH}"
+
   # import config
   . ${BACKUP_SCRIPT_PATH}/config
 else