Fix Tutorials/Examples

[itsdawei]

Description

Fix tutorials that were broken by previous changes.

TODO

• Lunar Lander
• LSI MNIST
• Arm Repertoire
• Fooling MNIST
• Sphere example
• Lunar Lander example

Questions

• Should we add jupyter notebook to setup.py, i.e. pip install -e pyribs[jupyter] -> no

Status

• I have read the guidelines in CONTRIBUTING.md
• I have formatted my code using yapf
• I have tested my code by running pytest
• I have linted my code with pylint
• I have added a one-line description of my change to the changelog in HISTORY.md
• This PR is ready to go

[btjanaka]

Note that the tutorials were failing due to kernelspec errors. This seems to be related to using the wrong Python version to open the notebooks -- see voila-dashboards/voila#267

I fixed this by opening the notebooks in jupyter lab with Python 3.7 and saving them after jupyterlab automatically corrected the kernelspec.