Fix code scanning alert - Fuzzing

[jenstroeger]

Tracking issue for:

• https://github.com/jenstroeger/python-package-template/security/code-scanning/34

We already use Hypothesis, and there are fuzzers like Atheris and Frelatage that we could consider for fuzzing. However, perhaps we should only mention those and leave it to users of this template to incorporate more diligent fuzz testing?