[0.5.0] export don't work when the database is password protected.

[tuxmaster5000]

Using an wrong password, then question comes again.
But using the right one will result in:

Traceback (most recent call last):
  File "/home/xxx/.local/bin/ffpass", line 8, in <module>
    sys.exit(main())
  File "/home/xxx/.local/lib/python3.9/site-packages/ffpass/__init__.py", line 419, in main
    args.func(args)
  File "/home/xxx/.local/lib/python3.9/site-packages/ffpass/__init__.py", line 322, in main_export
    logins = exportLogins(key, jsonLogins)
  File "/home/xxx/.local/lib/python3.9/site-packages/ffpass/__init__.py", line 217, in exportLogins
    decodeLoginData(key, encUsername),
  File "/home/xxx/.local/lib/python3.9/site-packages/ffpass/__init__.py", line 179, in decodeLoginData
    return PKCS7unpad(des.decrypt(ciphertext)).decode()
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xab in position 0: invalid start byte