[HANDS-ON BUG] Unit3 Colab GPU Error

# Describe the bug
I running [Unit3.jupyter](https://colab.research.google.com/github/huggingface/deep-rl-class/blob/main/notebooks/unit3/unit3.ipynb) in colab, and could not using GPU when I train model using this cell code
```python
!python -m rl_zoo3.train --algo dqn --env SpaceInvadersNoFrameskip-v4 -f logs/ -c dqn.yml
```
output
```
W tensorflow/compiler/tf2tensorrt/utils/py_utils.cc:38] TF-TRT Warning: Could not find TensorRT
```
I run this code make sure I hava a GPU
```python
print(tf.config.list_physical_devices('GPU'))
```
got response `[PhysicalDevice(name='/physical_device:GPU:0', device_type='GPU')]`

I search a lot, i look likes a tf question.

# Material

- Google Colab