Django 2.0.2 release notes

漏洞修复

• Fixed incorrect foreign key nullification if a model has two foreign keys to the same model and a target model is deleted ().
• Fixed regression in the use of followed by annotate() (#29067).
• Fixed a regression where contrib.auth.authenticate() crashes if an authentication backend doesn’t accept request and a later one does ().
• Fixed a regression where makemigrations crashes if a migrations directory doesn’t have an file (#29091).