Django 3.0.8 release notes

Django 3.0.8 fixes several bugs in 3.0.7.

• Fixed a regression in Django 3.0.7 that caused a queryset crash when grouping by a many-to-one relationship ().
• Fixed a regression in Django 3.0.2 that caused a migration crash on PostgreSQL when adding a foreign key to a model with a namespaced (#31735).