Add benchmark notebook (#5312)

* add notebook

* Créé avec Colaboratory

* move notebook to correct folder

* correct link

* correct filename

* correct filename

* better name

notebooks/README.md

@@ -17,6 +17,7 @@ Pull Request so it can be included under the Community notebooks.
 | [How to train a language model](https://github.com/huggingface/blog/blob/master/notebooks/01_how_to_train.ipynb)| Highlight all the steps to effectively train Transformer model on custom data | [![Open in Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/huggingface/blog/blob/master/notebooks/01_how_to_train.ipynb)|
 | [How to generate text](https://github.com/huggingface/blog/blob/master/notebooks/02_how_to_generate.ipynb)| How to use different decoding methods for language generation with transformers | [![Open in Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/huggingface/blog/blob/master/notebooks/02_how_to_generate.ipynb)|
 | [How to export model to ONNX](https://github.com/huggingface/transformers/blob/master/notebooks/04-onnx-export.ipynb) | Highlight how to export and run inference workloads through ONNX |
+| [How to use Benchmarks](https://github.com/huggingface/transformers/blob/master/notebooks/05-benchmark.ipynb) | How to benchmark models with transformers | [![Open in Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/huggingface/transformers/blob/master/notebooks/05-benchmark.ipynb)|
 
 
 ## Community notebooks: