Increase required version of optional Polymorphic Models for Django#1289

n2ygk merged 2 commits intodjango-json-api:maindjango-json-api/django-rest-framework-json-api:mainfrom

sliverc:django_polymorphic_versionsliverc/django-rest-framework-json-api:django_polymorphic_versionCopy head branch name to clipboard