Unable to build anymore on RTD

[submarcos]

Problem

RTD is not able to build doc with theme anymore

Reproducible Project

problem : https://readthedocs.org/projects/django-geostore/builds/12374842/
working : https://readthedocs.org/projects/django-geostore/builds/12280355/

[submarcos]

show when build was broken : https://readthedocs.org/projects/django-geostore/builds/