Update factory-boy to 2.9.1

[pyup-bot]

There's a new version of factory-boy available.
You are currently using 2.8.1. I have updated it to 2.9.1

These links might come in handy: PyPI | Changelog | Repo

Changelog

2.9.1

---

Bugfix:

• Fix packaging issues (see Tag formatter documentation zestsoftware/zest.releaser#212)
• Don't crash when debugging PostGenerationDeclaration

2.9.0

---

This version brings massive changes to the core engine, thus reducing the number of
corner cases and weird behaviourrs.

New:

• :issue:275: factory.fuzzy and factory.faker now use the same random seed.
• Add :class:factory.Maybe, which chooses among two possible declarations based
  on another field's value (powers the :class:~factory.Trait feature).
• :class:~factory.PostGenerationMethodCall only allows to pass one positional argument; use keyword arguments for
  extra parameters.

Deprecation:

• factory.fuzzy.get_random_state is deprecated, factory.random.get_random_state should be used instead.
• factory.fuzzy.set_random_state is deprecated, factory.random.set_random_state should be used instead.
• factory.fuzzy.reseed_random is deprecated, factory.random.reseed_random should be used instead.

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖

[pyup-bot]

Closing this in favor of #344