height and width in Resize pipeline are misplaced

**Reproduction**
```python
from mmgen.datasets.pipelines import Resize, LoadImageFromFile
results = {'real_img_path': 'path-to-img/0001.jpg'}
t = LoadImageFromFile(key='real_img', io_backend='disk')(results)
tt = Resize(keys=['real_img'], scale=(128, 32), keep_ratio=False)(t)
```

**Bug fix**
I think it's because mmcv.imresize uses (width, heights) for the scale argument.
