Add Fine-tune DialoGPT on new datasets notebook
Here is a tutorial notebook I created for fine-tuning the DialoGPT on a Spanish conversation dataset. It shows how to prepare a dataset that conforms to the necessary style of the original DialoGPT dataset and how to train it using a GPU provided by Google Colab. Sadly it is not using the newer Trainer that Huggingface provides, but I thought it might be useful for others trying to work with conversational AI so wanted to share.

Thanks for the amazing library and hugs to all of y'all 🤗! 



# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/4473?src=pr&el=h1) Report
> Merging [#4473](https://codecov.io/gh/huggingface/transformers/pull/4473?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/48c3a70b4eaedab1dd9ad49990cfaa4d6cb8f6a0&el=desc) will **decrease** coverage by `0.42%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/4473/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/4473?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #4473      +/-   ##
==========================================
- Coverage   78.41%   77.98%   -0.43%     
==========================================
  Files         123      123              
  Lines       20432    20432              
==========================================
- Hits        16021    15934      -87     
- Misses       4411     4498      +87     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/4473?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/data/processors/squad.py](https://codecov.io/gh/huggingface/transformers/pull/4473/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9kYXRhL3Byb2Nlc3NvcnMvc3F1YWQucHk=) | `28.66% <0.00%> (-28.03%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/4473/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl91dGlscy5weQ==) | `88.66% <0.00%> (+0.16%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/4473?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/4473?src=pr&el=footer). Last update [48c3a70...8518af3](https://codecov.io/gh/huggingface/transformers/pull/4473?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
<|||||>Cool notebook! And a great complement to the [model card](https://huggingface.co/ncoop57/DiGPTame-medium) 

cc @patrickvonplaten 

Maybe you can use the `Trainer` in a v2 of the notebook =)

And you could use the [nlp](https://github.com/huggingface/nlp) library to share the dataset, cc @thomwolf <|||||>Awesome! 