TypeError: __init__() got an unexpected keyword argument 'vocab_file' in transformers/tokenization_gpt2.py", line 380
## 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: 3.3.1
- `tokenizers` version: 0.9.2
- Platform: Linux-3.10.0-1062.4.1.el7.x86_64-x86_64-with-redhat-7.7-Maipo
- Python version: 3.7.6
- PyTorch version (GPU?): 1.6.0 (False)
- Tensorflow version (GPU?): 2.3.1 (False)
- Using GPU in script?: no
- Using distributed or parallel set-up in script?: no


### Who can help @mfuntowicz 
## Information

Model I am using (Bert, XLNet ...): RoBERTa-base

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)
fairseq

## To reproduce

I use the **RobertaTokenizerFast** and it seems an arg name mismatch.
Steps to reproduce the behavior:

1. self.tokenizer = RobertaTokenizerFast.from_pretrained('roberta-base', cache_dir=args.cache_dir)

In transformers.tokenization_gpt2.py L376 it is:
`ByteLevelBPETokenizer(
                vocab_file=vocab_file,
                merges_file=merges_file,
                add_prefix_space=add_prefix_space,
                trim_offsets=trim_offsets,
            )`

But in tokenizers.implementations.ByteLevelBPETokenizer it is expected to be `vocab`.


## Expected behavior
`  File "/zfs1/hdaqing/rum20/kp/fairseq-kpg/fairseq/data/encoders/hf_bpe.py", line 31, in __init__
    self.tokenizer = RobertaTokenizerFast.from_pretrained(args.pretrained_model, cache_dir=args.cache_dir)
  File "/ihome/hdaqing/rum20/anaconda3/envs/kp/lib/python3.7/site-packages/transformers/tokenization_utils_base.py", line 1428, in from_pretrained
    return cls._from_pretrained(*inputs, **kwargs)
  File "/ihome/hdaqing/rum20/anaconda3/envs/kp/lib/python3.7/site-packages/transformers/tokenization_utils_base.py", line 1575, in _from_pretrained
    tokenizer = cls(*init_inputs, **init_kwargs)
  File "/ihome/hdaqing/rum20/anaconda3/envs/kp/lib/python3.7/site-packages/transformers/tokenization_roberta.py", line 380, in __init__
    **kwargs,
  File "/ihome/hdaqing/rum20/anaconda3/envs/kp/lib/python3.7/site-packages/transformers/tokenization_gpt2.py", line 380, in __init__
    trim_offsets=trim_offsets,
TypeError: __init__() got an unexpected keyword argument 'vocab_file'`

same issue<|||||>Hello! I think this is due to a mismatch between your `transformers` and `tokenizers` versions. `transformers` version v3.3.1 expects `tokenizers == 0.8.1.rc2`.

If you want to use `tokenizers == 0.9.2` you should work on the current `master` branch or wait for version v3.4.0 which should be released sometimes today.<|||||>Thank you! I upgraded both and it works.