Add FactoryBot/AssociationStyle cop

[r7kamura]

Recreated from the following pull request:

• Add RSpec/FactoryBot/AssociationStyle cop rubocop-rspec#1414

---

Before submitting the PR make sure the following are checked:

• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Updated documentation.
• Added an entry to the CHANGELOG.md if the new code introduces user-observable changes.
• The build (bundle exec rake) passes (be sure to run this locally, since it may produce updated documentation that you will need to commit).

If you have created a new cop:

• Added the new cop to config/default.yml.
• The cop is configured as Enabled: pending in config/default.yml.
• The cop documents examples of good and bad code.
• The tests assert both that bad code is reported and that good code is not reported.
• Set VersionAdded: "<<next>>" in default/config.yml.

If you have modified an existing cop's configuration options:

• Set VersionChanged: "<<next>>" in config/default.yml.

[pirj]

Looks great, thank you!
I've applied some cosmetic clean-up.

[pirj]

lib/rubocop/cop/factory_bot/association_style.rb:174:25: C: InternalAffairs/UndefinedConfig: NonImplicitAssociationMethodNames is not defined in the configuration for FactoryBot/AssociationStyle in config/default.yml.
            (cop_config['NonImplicitAssociationMethodNames'] || [])
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Locally 🧐

$ rubocop -v
v1.50.2

Updated to the latest 1.51.0, but still the same. It seems to be a rubocop bug to me.
Green on ci, so no problem.

PS most probably caused by rubocop-rspec's config somehow being preferred over rubocop-factory_bot's one, as witnessed by such messages:

/Users/pirj/.rvm/gems/ruby-3.1.0@rubocop-factory_bot/gems/rubocop-rspec-2.20.0/config/default.yml: FactoryBot/FactoryNameStyle has the wrong namespace - should be RSpec/FactoryBot

[ydah]

Thank you!

[pirj]

@ydah Are you ok with this?
We can merge and release everything we have stacked up in a minor version, as it's the last PR remaining.

[ydah]

Thank you!

[pirj]

Thank you, @r7kamura ! :combo: 1️⃣ 2️⃣ 3️⃣ 🥇