[Bug] Digits DA example failed, likely due to updates
# 🐛 Bug

Digits DA example failed, likely due to updated torchvision (or PL)

## To reproduce

Run https://colab.research.google.com/github/pykale/pykale/blob/main/examples/digits_dann_lightn/tutorial.ipynb#scrollTo=DiEqCANrpAy1

** Stack trace/error message **
```
import logging
import os

from config import get_cfg_defaults
import numpy as np
import pytorch_lightning as pl
import torch
from torch.utils.data import DataLoader
from torch.utils.data import SequentialSampler
import torchvision

from model import get_model
from pytorch_lightning.callbacks import ModelCheckpoint
from pytorch_lightning.loggers import TensorBoardLogger

from kale.loaddata.image_access import DigitDataset
from kale.loaddata.multi_domain import MultiDomainDatasets
from kale.utils.seed import set_seed

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
<ipython-input-2-76f9aafdc93d> in <module>()
     10 import torchvision
     11 
---> 12 from model import get_model
     13 from pytorch_lightning.callbacks import ModelCheckpoint
     14 from pytorch_lightning.loggers import TensorBoardLogger

2 frames
/usr/local/lib/python3.7/dist-packages/kale/embed/video_i3d.py in <module>()
     12 import torch.nn as nn
     13 import torch.nn.functional as F
---> 14 from torchvision.models.utils import load_state_dict_from_url
     15 
     16 model_urls = {

ModuleNotFoundError: No module named 'torchvision.models.utils'

---------------------------------------------------------------------------
NOTE: If your import is failing due to a missing package, you can
manually install dependencies using either !pip or !apt.

To view examples of installing some common dependencies, click the
"Open Examples" button below.
---------------------------------------------------------------------------
```
diff --git a/kale/embed/video_i3d.py b/kale/embed/video_i3d.py
index 69f42fc..be9a445 100644
--- a/kale/embed/video_i3d.py
+++ b/kale/embed/video_i3d.py
@@ -11,7 +11,7 @@ https://github.com/deepmind/kinetics-i3d/blob/master/i3d.py
 import torch
 import torch.nn as nn
 import torch.nn.functional as F
-from torchvision.models.utils import load_state_dict_from_url
+from torch.hub import load_state_dict_from_url
 
 model_urls = {
     "rgb_imagenet": "https://github.com/XianyuanLiu/pytorch-i3d/raw/master/models/rgb_imagenet.pt",
['kale/embed/video_i3d.py']