DeBERTa v2 throws "TypeError: stat: path should be string...", v1 not
## Environment info
<!-- You can run the command `transformers-cli env` and copy-and-paste its output below.
     Don't forget to fill out the missing fields in that output! -->

- `transformers` version: 4.3.1
- Platform: Linux-5.4.0-54-generic-x86_64-with-glibc2.29
- Python version: 3.8.5
- PyTorch version (GPU?): 1.7.1+cpu (False)
- Tensorflow version (GPU?): not installed (NA)
- Using GPU in script?: false
- Using distributed or parallel set-up in script?: false

### Who can help

@BigBird01 @patil-suraj 

## Information

Model I am using (DeBERTa v2):

The problem arises when using:
* [x] the official example scripts: (give details below)
* [ ] my own modified scripts: (give details below)

The tasks I am working on is:
* [ ] an official GLUE/SQUaD task: (give the name)
* [ ] my own task or dataset: (give details below)

## To reproduce

Steps to reproduce the behavior:

1. Create this file:
```
from transformers import AutoTokenizer, AutoModel
import torch

tokenizer = AutoTokenizer.from_pretrained('microsoft/deberta-xlarge-v2')
model = AutoModel.from_pretrained('microsoft/deberta-xlarge-v2')

inputs = tokenizer("Hello, my dog is cute", return_tensors="pt")
outputs = model(**inputs)

last_hidden_states = outputs.last_hidden_state
print(outputs)
```

2. Run the file

3. You'll get:
```
(venv) root@16gb:~/deberta# python3 index.py
Traceback (most recent call last):
  File "index.py", line 4, in <module>
    tokenizer = AutoTokenizer.from_pretrained('microsoft/deberta-xlarge-v2')
  File "/root/deberta/venv/lib/python3.8/site-packages/transformers/models/auto/tokenization_auto.py", line 398, in from_pretrained
    return tokenizer_class_py.from_pretrained(pretrained_model_name_or_path, *inputs, **kwargs)
  File "/root/deberta/venv/lib/python3.8/site-packages/transformers/tokenization_utils_base.py", line 1788, in from_pretrained
    return cls._from_pretrained(
  File "/root/deberta/venv/lib/python3.8/site-packages/transformers/tokenization_utils_base.py", line 1860, in _from_pretrained
    tokenizer = cls(*init_inputs, **init_kwargs)
  File "/root/deberta/venv/lib/python3.8/site-packages/transformers/models/deberta/tokenization_deberta.py", line 542, in __init__
    if not os.path.isfile(vocab_file):
  File "/usr/lib/python3.8/genericpath.py", line 30, in isfile
    st = os.stat(path)
TypeError: stat: path should be string, bytes, os.PathLike or integer, not NoneType
```

I tried this with the DeBERTa v1 models and there was no error. I've the same behavior when using `DebertaTokenizer, DebertaModel`

## Expected behavior

No error.
Hi @205g0 

Thank you for reporting this! 

`microsoft/deberta-xlarge-v2` uses `sentencepiece` vocab and it's not implemented for deberta, which is the reason for this error. <|||||>Hey Suraj, thanks for the quick response and good to know!<|||||>@BigBird01  do you think you could add the missing tokenizer, otherwise, I could add it. Thanks!<|||||>DeBERTa-v2 is not available in the library yet. We're working towards it with @BigBird01.<|||||>Thanks @205g0  for the interest in DeBERTa-v2. We are working on it with @LysandreJik, hopefully, it will be available soon.  You can check our [PR](https://github.com/huggingface/transformers/pull/10018) for the progress.<|||||>Oh sorry, @BigBird01, I did not realize that this was a work in progress<|||||>> Oh sorry, @BigBird01, I did not realize that this was a work in progress

No worry, @patil-suraj. Thanks for your quick response. We are glad to integrate these SOTA NLU models with HF to benefit the community:) <|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/master/CONTRIBUTING.md) are likely to be ignored.