Use the ipaddress module to detect valid IPV6

[azmeuk]

I was surprised to see that furl would allow invalid but well-formed IPV6:

furl/tests/test_furl.py

Lines 1658 to 1661 in 7748462

	# Invalid, but well-formed, IPv6 addresses shouldn't raise an
	# exception because urlparse.urlsplit() doesn't raise an
	# exception on invalid IPv6 addresses.
	furl.furl('http://[0:0:0:0:0:0:0:1:1:1:1:1:1:1:1:9999999999999]/')

I would suggest to use the IPV6Address object from the python3 ipaddress module to validate IPV6. For python2 I would suggest using the ipaddress backport on pypi.

If it is OK I would volunteer for a PR. What do you think?

[vcunat]

With python 3.11.4 it fails already without changing anything in furl? I'm getting

=========================== short test summary info ============================
FAILED tests/test_furl.py::TestFurl::test_hosts - ValueError: '0:0:0:0:0:0:0:1:1:1:1:1:1:1:1:9999999999999' does not appear t...
FAILED tests/test_furl.py::TestFurl::test_netloc - ValueError: '0:0:0:0:0:0:0:1:1:1:1:1:1:1:1:9999999999999' does not appear t...
========================= 2 failed, 76 passed in 7.41s =========================