`aset` / `aget` not on `BaseCache` type stubs

[AngellusMortis]

Bug report

What's wrong

The async interface for BaseCache was added in 4.0, not 4.1. This is now causing mypy errors for 4.0.5 saying aget / aset does not exist.

https://github.com/django/django/blob/4.0.5/django/core/cache/backends/base.py#L149

4.1 adds the async ORM interface. 4.0 was cache interface.

Introduced in https://github.com/typeddjango/django-stubs/pull/998

How is that should be

aset and aget should be in the type stubs for BaseCache.

System information

• OS:
• python version:
• django version: 4.0.5
• mypy version:
• django-stubs version: 1.12.0
• django-stubs-ext version: