Fix Call to IPAddress.is_private() removed method.

[arouze]

Hello 👋

Thanks for your work !
I have an issue with your package on homeassistant.

here the message when I try to access to the sensor :

ERROR (MainThread) [homeassistant.components.sensor] Error while setting up bbox platform for sensor
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/entity_platform.py", line 361, in _async_setup_platform
    await asyncio.shield(awaitable)
  File "/usr/local/lib/python3.12/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/bbox/sensor.py", line 104, in setup_platform
    bbox_data.update()
  File "/usr/src/homeassistant/homeassistant/util/__init__.py", line 184, in wrapper
    result = method(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/bbox/sensor.py", line 198, in update
    box = pybbox.Bbox()
          ^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/pybbox/__init__.py", line 21, in __init__
    self.bbox_url = BboxAPIUrl(None, None, ip)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/pybbox/bboxApiURL.py", line 25, in __init__
    self.build_url_request()
  File "/usr/local/lib/python3.12/site-packages/pybbox/bboxApiURL.py", line 53, in build_url_request
    if net.IPAddress(self.ip).is_private():
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'IPAddress' object has no attribute 'is_private'

It seems that the is_private() method was delete in [email protected].
This PR just replace the is_private method by the is_ipv4_private_use (bbox use only ipv4 right ?! ).

BTW, I'm not a python developper, sooo if you want to check / drop / update by PR it's fine !