Codecov setup
Setup codecov
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/4768?src=pr&el=h1) Report
> Merging [#4768](https://codecov.io/gh/huggingface/transformers/pull/4768?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/2b8b6c929e282958a920ba2aa26ee59106986ec3&el=desc) will **increase** coverage by `0.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/4768/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/4768?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #4768      +/-   ##
==========================================
+ Coverage   77.31%   77.33%   +0.01%     
==========================================
  Files         128      128              
  Lines       21059    21059              
==========================================
+ Hits        16282    16285       +3     
+ Misses       4777     4774       -3     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/4768?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/file\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/4768/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9maWxlX3V0aWxzLnB5) | `73.85% <0.00%> (-0.42%)` | :arrow_down: |
| [src/transformers/modeling\_openai.py](https://codecov.io/gh/huggingface/transformers/pull/4768/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ19vcGVuYWkucHk=) | `82.03% <0.00%> (+1.35%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/4768?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/4768?src=pr&el=footer). Last update [2b8b6c9...fc6d7f5](https://codecov.io/gh/huggingface/transformers/pull/4768?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
