Most of this was fixed by adding the `attribute-defined-statically-cop`
branch of `thoughtbot/rubocop-rspec` to the Gemfile and running:
```sh
rubocop \
--require rubocop-rspec \
--only FactoryBot/AttributeDefinedStatically \
--auto-correct
```
I had to update the cucumber tests manually, and I realized our changes
don't handle `ignore` blocks or blocks with arity 1 that use the yielded
DefinitionProxy. I will update
https://github.com/rubocop-hq/rubocop-rspec/pull/666to handle these
cases.
Declarations are another layer of abstraction between defining the
factories via the DSL and compiling the factories and their attributes.
Declarations know how to return their attribute(s), and running a
factory compiles the declarations before building all attributes on the
factory. This moves all the attribute compilation logic into one
centralized location on the Factory instance, which means traits (and
potentially other features down the road) can have individual attributes
overridden within child factories or through FactoryGirl.modify
Closes#205
