`DebertaTokenizer` always assigns token type ID 0
## Environment info

- `transformers` version: 4.16.2
- Platform: Linux-5.15.13-051513-generic-x86_64-with-glibc2.34
- Python version: 3.9.7
- PyTorch version (GPU?): 1.9.0+cu111 (True)
- Tensorflow version (GPU?): not installed (NA)
- Flax version (CPU?/GPU?/TPU?): not installed (NA)
- Jax version: not installed
- JaxLib version: not installed
- Using GPU in script?: no
- Using distributed or parallel set-up in script?: no


### Who can help
@LysandreJik 

## Information

Model I am using (Bert, XLNet ...): `microsoft/deberta-large`

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

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

## To reproduce

Steps to reproduce the behavior:

Run this code:
```python
from transformers import AutoTokenizer
tokenizer = AutoTokenizer.from_pretrained("microsoft/deberta-large")
print(tokenizer("Hello", "World"))
```

It outputs:
```
{'input_ids': [1, 31414, 2, 10988, 2], 'token_type_ids': [0, 0, 0, 0, 0], 'attention_mask': [1, 1, 1, 1, 1]}
```

Even though I put in two sequences, all `token_type_ids` are 0.

## Expected behavior

The tokens from the second sequence should get type ID 1. `token_type_ids` should be `[0, 0, 0, 1, 1]`.
Looks like this is the change that introduced this behavior.

https://github.com/huggingface/transformers/commit/57c1749efabf5c86bcfd4e4e078567a63a7c8a81#diff-7ff4f35b72b8541520ea52c851b55bc2682da83e01e6e0ceeb5289f7dd2f0620R217
<|||||>Good catch! Would you like to open a PR to fix this?<|||||>I'll give this a try!