Migration broken in 5.1

[mikewolfd]

Checklist

• [X] I have verified that I am using a GIS-enabled database, such as PostGIS or Spatialite.
• [X] I have verified that that issue exists against the master branch of django-cities.
• [X] I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• [X] I have reduced the issue to the simplest possible case.
• [X] I have included a failing test as a pull request. (If you are unable to do so we can still accept the issue.)

Steps to reproduce

Django 5.1

Expected behavior

No new migrations are created

Actual behavior

Migration 13 is created with a similar issue to what was fixed in 0.6.2.

WARNINGS: cities.Country.neighbours: (fields.W345) related_name has no effect on ManyToManyField with a symmetrical relationship, e.g. to "self". Migrations for 'cities': /usr/local/lib/python3.12/site-packages/cities/migrations/0013_alter_alternativename_id_alter_city_id_and_more.py ~ Alter field id on alternativename ~ Alter field id on city ~ Alter field id on continent ~ Alter field id on country ~ Alter field id on district ~ Alter field id on postalcode ~ Alter field id on region ~ Alter field id on subregion