update tutorial to reflect environment class updates

[satra]

@djarecka - is this still valid? https://nipype.github.io/pydra-tutorial/notebooks/5_intro_shelltask.html#dockertask

[bclenet]

Hi, section 5.4. DockerTask of the tutorial does not work with pydra 0.23, as it raises the following error :
AttributeError: module 'pydra' has no attribute 'DockerTask'

Still with pydra 0.23, section 5.4.1.1. Using ShellCommandTask with container_info argument would not work as expected either. The two pieces of code (with or without container_info) return the same result.

[djarecka]

@bclenet - thank you for pointing to this.