Update nvidia-container-toolkit installation

The tag `latest` has been deprecated by NVIDIA:
NVIDIA/nvidia-container-toolkit#302 (comment)
Therefore, the provided command is deprecated:
`docker run --gpus all --rm nvidia/cuda nvidia-smi`
Unable to find image 'nvidia/cuda:latest' locally
docker: Error response from daemon: manifest for nvidia/cuda:latest not found: manifest unknown: manifest unknown.
See 'docker run --help'.
sudo docker run --gpus all --rm nvidia/cuda nvidia-smi
Unable to find image 'nvidia/cuda:latest' locally
docker: Error response from daemon: manifest for nvidia/cuda:latest not found: manifest unknown: manifest unknown.
See 'docker run --help'.
Updated command found here:
https://docs.nvidia.com/datacenter/cloud-native/container-toolkit/latest/sample-workload.html#running-a-sample-workload-with-docker

Author: MartinJrgsn

site/en/install/docker.md

@@ -130,7 +130,7 @@ lspci | grep -i nvidia
 Verify your `nvidia-docker` installation:
 
 <pre class="devsite-terminal devsite-click-to-copy">
-docker run --gpus all --rm nvidia/cuda nvidia-smi
+sudo docker run --rm --runtime=nvidia --gpus all ubuntu nvidia-smi
 </pre>
 
 Note: `nvidia-docker` v2 uses `--runtime=nvidia` instead of `--gpus all`. `nvidia-docker` v1 uses the `nvidia-docker` alias,