Converting marian tatoeba models
## Environment info

- `transformers` version: 4.4.2
- Platform: Linux-4.19.112+-x86_64-with-Ubuntu-18.04-bionic
- Python version: 3.7.10
- PyTorch version (GPU?): 1.8.0+cu101 (False)
- Tensorflow version (GPU?): 2.4.1 (False)
- Using GPU in script?: False
- Using distributed or parallel set-up in script?: False

### Who can help

- marian: @patrickvonplaten, @patil-suraj

## Information

Model I am using (Bert, XLNet...): marian

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

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

## To reproduce

Steps to reproduce the behavior:

All steps are the same as in [official script](https://github.com/huggingface/transformers/blob/master/scripts/tatoeba/README.md) for converting marian tatoeba models to pytorch.

Error log:
```
Traceback (most recent call last):
  File "src/transformers/models/marian/convert_marian_tatoeba_to_pytorch.py", line 1267, in <module>
    resolver = TatoebaConverter(save_dir=args.save_dir)
  File "src/transformers/models/marian/convert_marian_tatoeba_to_pytorch.py", line 80, in __init__
    released.columns = released_cols
  File "/usr/local/lib/python3.7/dist-packages/pandas/core/generic.py", line 5154, in __setattr__
    return object.__setattr__(self, name, value)
  File "pandas/_libs/properties.pyx", line 66, in pandas._libs.properties.AxisProperty.__set__
  File "/usr/local/lib/python3.7/dist-packages/pandas/core/generic.py", line 564, in _set_axis
    self._mgr.set_axis(axis, labels)
  File "/usr/local/lib/python3.7/dist-packages/pandas/core/internals/managers.py", line 227, in set_axis
    f"Length mismatch: Expected axis has {old_len} elements, new "
ValueError: Length mismatch: Expected axis has 7 elements, new values have 9 elements
```

## Expected behavior

IMO, main problem is in changes in fields of file [Tatoeba-Challenge/models/released-models.txt](https://github.com/Helsinki-NLP/Tatoeba-Challenge/blob/master/models/released-models.txt). 
I'm expecting clean conversion of model for choosed language pair.
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.<|||||>@patil-suraj unstale?<|||||>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.<|||||>Unstale<|||||>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.<|||||>Unstale<|||||>@patil-suraj - do you think you find time to take a look here? Otherwise I can probably free some time for it<|||||>I will take a look at it this week.<|||||>Gently pinging @patil-suraj here again - I think the conversion works now no? Could you maybe check? :-)<|||||>The conversion should work now, it has been fixed in #13757