Simplify GPU detection in docker launch script (#2064)

Co-authored-by: Antonin RAFFIN <[email protected]>

scripts/run_docker_gpu.sh

@@ -1,19 +1,12 @@
 #!/bin/bash
 # Launch an experiment using the docker gpu image
-
 cmd_line="$@"
-
 echo "Executing in the docker (gpu image):"
 echo $cmd_line
 
-# TODO: always use new-style once sufficiently widely used (probably 2021 onwards)
-if [ -x "$(which nvidia-docker)" ]; then
-  # old-style nvidia-docker2
-  NVIDIA_ARG="--runtime=nvidia"
-else
-  NVIDIA_ARG="--gpus all"
-fi
+# Using new-style GPU argument
+NVIDIA_ARG="--gpus all"
 
 docker run -it ${NVIDIA_ARG} --rm --network host --ipc=host \
-  --mount src=$(pwd),target=/home/mamba/stable-baselines3,type=bind stablebaselines/stable-baselines3:latest \
-  bash -c "cd /home/mamba/stable-baselines3/ && $cmd_line"
+--mount src=$(pwd),target=/home/mamba/stable-baselines3,type=bind stablebaselines/stable-baselines3:latest \
+bash -c "cd /home/mamba/stable-baselines3/ && $cmd_line"