[#3402] CITATION

[caramelomartins]

This PR was submitted to resolve #3402.

I have decided to include all named authors in setup.py because I felt it was fair. Depending on the citation style, the person citing will either name all the authors or use the et al. format - like I have suggested in the text-based citation.

Most of CITATION was copied from what was written for hypothesis.

Checklist:

• Create a new changelog file in the changelog folder, with a name like <ISSUE NUMBER>.<TYPE>.rst. See changelog/README.rst for details.
• Target the master branch for bug fixes, documentation updates and trivial changes.

Not Applicable:

• Target the features branch for new features and removals/deprecations.
• Include documentation when adding new features.
• Include new tests or update existing tests when applicable.

[coveralls]

Coverage increased (+0.05%) to 92.655% when pulling 6a4fa4f on caramelomartins:master into 0565a7a on pytest-dev:master.

[nicoddemus]

Awesome, thanks @caramelomartins!

[caramelomartins]

@nicoddemus 👍