谢昕辰 a947e3e754
[FIx] Set default backend_args values to None (#2597)
## Motivation

In MMEngine >= 0.2.0, it might directly determine what the backend is by
using the `data_root` path.

## Modification

Set all default `backend_args` values are `None`.
2023-02-16 15:33:52 +08:00
..
2022-07-29 18:37:20 +08:00