[9.x] Add ->set() method to factory

[ralphjsmit]

Lately I've been writing unit-tests for the models of an application that did not have many tests yet. In that application many scopes were used.

I noticed that I was often creating models like this, where you just need to make one little change every time:

EloquentModel::factory()
    ->create(['name' => 'foo']);

EloquentModel::factory()
    ->someMethod()
    ->create(['country' => 'NL']);

I figured out that the tests would look a lot cleaner if we could just get rid of those single-item arrays, so I came up with a small method called ->set(). This method is in my eyes easier and more expressive than ->create(['foo' => 'bar']), because it is immediately clear that we're setting only a single property here.

EloquentModel::factory()
    ->set('name', 'foo')
    ->create();

EloquentModel::factory()
    ->someMethod()
    ->set('country', 'NL')
    ->create();

Another option would be to name the method ->put(), in line with the similar collection method (but personally I prefer ->set()).