www/py-django-netfields: Update to 1.2.4

• Also assume maintainership.

Changelog since 1.2.2:

https://github.com/jimfunk/django-postgresql-netfields/blob/v1.2.4/CHANGELOG

PR: 258461
Approved by: maintainer timeout (+14 days)
MFH: 2021Q4

(cherry picked from commit deddeae48f578360135a9e6ca95c3b3688db718a)