Update example_submission_script.sh

I added srun to perform multi-node training with the singularity container.

example_submission_script.sh

@@ -9,5 +9,5 @@ module load Singularity-Tools
 echo "-------- Outside of the container -----------"
 python src/hello_world.py
 echo "-------- Inside of the container ------------"
-singularity run singularity_docker_jupyter.sif python3 src/hello_world.py
+srun singularity run singularity_docker_jupyter.sif python3 src/hello_world.py
 echo "--------------------------------------------"