Multi file transcription doesn't work

Hello,
I've tried again the multi file transcription, this time with files that do not have spaces in their names. Still it converts only the first file.

This is the command I use:
`vosk-transcriber -l it -i ./folder`

This is the log:

```
INFO:root:Execution time: 617.106 sec; xRT 0.117
Traceback (most recent call last):
File "/home/ale/.local/bin/vosk-transcriber", line 8, in
sys.exit(main())
File "/home/ale/.local/lib/python3.8/site-packages/vosk/transcriber/cli.py", line 82, in main
transcriber.process_task_list(args, task_list)
File "/home/ale/.local/lib/python3.8/site-packages/vosk/transcriber/transcriber.py", line 170, in process_task_list
self.process_task_list_pool(task_list)
File "/home/ale/.local/lib/python3.8/site-packages/vosk/transcriber/transcriber.py", line 166, in process_task_list_pool
pool.map(self.pool_worker, task_list)
File "/usr/lib/python3.8/multiprocessing/pool.py", line 364, in map
return self._map_async(func, iterable, mapstar, chunksize).get()
File "/usr/lib/python3.8/multiprocessing/pool.py", line 771, in get
raise self._value
File "/usr/lib/python3.8/multiprocessing/pool.py", line 125, in worker
result = (True, func(*args, **kwds))
File "/usr/lib/python3.8/multiprocessing/pool.py", line 48, in mapstar
return list(map(*args))
File "/home/ale/.local/lib/python3.8/site-packages/vosk/transcriber/transcriber.py", line 156, in pool_worker
logging.info('Execution time: {:.3f} sec; xRT {:.3f}'.format(elapsed, float(elapsed) * (2 * SAMPLE_RATE) / tot_samples))
ZeroDivisionError: float division by zero
```
Thank you a lot!