Still checkpointing problems

I reported earlier in #1269 that the example wasn't working and I just checked the latest version on main to see whether it works and I get

```
(avalanche) 147ddaa47ac3:examples marwistu$ python checkpointing.py --cuda -1
Using device cpu
Traceback (most recent call last):
File "/Users/marwistu/avalanche/examples/checkpointing.py", line 96, in
main_with_checkpointing(parser.parse_args())
File "/Users/marwistu/avalanche/examples/checkpointing.py", line 61, in main_with_checkpointing
strategy = Naive(
File "/Users/marwistu/miniconda/miniconda3/envs/avalanche/lib/python3.9/site-packages/avalanche/training/supervised/strategy_wrappers.py", line 100, in __init__
super().__init__(
File "/Users/marwistu/miniconda/miniconda3/envs/avalanche/lib/python3.9/site-packages/avalanche/training/templates/common_templates.py", line 128, in __init__
super().__init__() # type: ignore
TypeError: __init__() missing 2 required positional arguments: 'model' and 'optimizer'
```

Besides that, I still cannot load checkpoints as mentioned in #1270 with the latest Pytorch 1 version as also observed by someone else in that issue. I wasn't able to replicate with a simple example as above since this isn't working at the moment. My code works with Pytorch 1.12 but I would like to upgrade to 1.13 for some other dependencies I am using.