feat: add compatibility with django-allauth v65.4

[browniebroke]

• Prefer the new LOGIN_METHODS when available
• Fallback to AUTHENTICATION_METHOD. Should keep dj-rest-auth working with older allauth versions
• Once dj-rest-auth wants to drop support for django-allauth < 65.4:
  • Remove the branches with AUTHENTICATION_METHOD
  • Update the minimum allauth version in setup.py (and docs, if needed)

Fix #679

[sipa-echo-zaoa]

Hi @iMerica,
Could you please merge this PR?
Getting these warning messages every time a command is run is getting pretty annoying.
Thank you.

[evdutt]

@iMerica Can you please take a look at this PR so I can stop getting warnings? Thanks!

In the meantime, I added the following to my settings to suppress this.

import warnings

warnings.filterwarnings(
'ignore',
message='app_settings.AUTHENTICATION_METHOD is deprecated, use: app_settings.LOGIN_METHODS',
category=UserWarning,
module='dj_rest_auth.serializers'
)

[onny]

Trying to use this with django-allauth 65.9 I get this error while running tests

       > ======================================================================
       > ERROR [0.001s]: dj_rest_auth.tests.test_social (unittest.loader._FailedTest.dj_rest_auth.tests.test_social)
       > ----------------------------------------------------------------------
       > ImportError: Failed to import test module: dj_rest_auth.tests.test_social
       > Traceback (most recent call last):
       >   File "/nix/store/sd81bvmch7njdpwx3lkjslixcbj5mivz-python3-3.13.4/lib/python3.13/unittest/loader.py", line 396, in _find_test_path
       >     module = self._get_module_from_name(name)
       >   File "/nix/store/sd81bvmch7njdpwx3lkjslixcbj5mivz-python3-3.13.4/lib/python3.13/unittest/loader.py", line 339, in _get_module_from_name
       >     __import__(name)
       >     ~~~~~~~~~~^^^^^^
       >   File "/build/source/dj_rest_auth/tests/test_social.py", line 5, in <module>
       >     from allauth.socialaccount.providers.facebook.provider import GRAPH_API_URL
       > ImportError: cannot import name 'GRAPH_API_URL' from 'allauth.socialaccount.providers.facebook.provider' (/nix/store/crzcnj72srj6wb0ar5r2w0hcs04jhpsx-python3.13-django-allauth-65.9.0/lib/python3.13/site-packages/allauth/socialaccount/providers/facebook/provider.py)
       >
       >
       > ----------------------------------------------------------------------
       > Ran 59 tests in 68.187s
       >
       > FAILED (errors=1)