Deprecated pip package install sample

[LeandroVidal555]

https://github.com/aws-samples/amazon-sagemaker-notebook-instance-lifecycle-config-samples/blob/master/scripts/install-pip-package-single-environment/on-start.sh

This script does not work for me, at least when using it on a lifecycle configuration, attaching it to my domain and then lauching a Jupyter Lab Space.

The user "ec2-user" does not even exist.