Test pyribs installation in tutorials

[btjanaka]

Description

Previously, we always installed ribs[visualize] before testing tutorials. This led to uncaught bugs where some tutorials needed ribs[visualize] to be installed but did not install it -- namely, since we always installed ribs[visualize], the tutorial could get by without installing ribs[visualize]. This led to bugs such as those in #379. To remedy this issue, this PR removes the default installation of ribs[visualize] in the tutorial CI.

Instead, the notebook now installs the local copy of pyribs on its own -- we do this by replacing, e.g., pip install ribs[visualize] with pip install .[visualize]. Note that it is not possible to leave this dependency as is (i.e., pip install ribs[visualize]) because the tutorial would pull from PyPI instead of the local copy.

TODO

• Fix bug in fooling mnist tutorial caused by matplotlib not being installed

Questions

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