Dockerfile doesn't work anymore

I had several issues running dopamine with [the last docker image](https://github.com/google/dopamine/blob/master/docker/core/Dockerfile) because of the last Jax and CUDA changes. Particularly with the cudnn versions.

I made the following changes to the dockerfile and managed to the image successfully in a gpu:

- Changed [this](https://github.com/google/dopamine/blob/1cbed6c7c35163e73b0ee2f2d2bf032b057570dd/docker/core/Dockerfile#L6) line with `ARG cuda_docker_tag="11.4.2-cudnn8-devel-ubuntu20.04"` to update the docker cuda image to 11.4.2:

- Changed [this](https://github.com/google/dopamine/blob/1cbed6c7c35163e73b0ee2f2d2bf032b057570dd/docker/core/Dockerfile#L36) line to `RUN pip install --upgrade "jax[cuda]" -f https://storage.googleapis.com/jax-releases/jax_releases.html ` since the installation command changed.