Fix deprecated use of config.action_mailer.preview_path = in favor of ...preview_paths << to support Rails 7.1 upgrade

[alexevanczuk]

Fixes #2703

Also see rails/rails#31595, particularly this comment

[JonRowe]

Thanks, I'm actually working on this myself at the moment as its not quite this simple, we need to support both methods and also fix that check

[alexevanczuk]

Gotcha @JonRowe. Do you know where I can find what versions of Rails that rspec-rails currently supports? I wonder if we could just check rails version and use the new api if the version is greater than or equal to the version of rails that introduced the api. What do ya think?

[pirj]

use rspec-rails 6.x for Rails 6.1 or 7.x.

check rails version

Or like this

rspec-rails/lib/rspec/rails/fixture_support.rb

Line 25 in 9681266

if respond_to?(:fixture_paths=)

[JonRowe]

We support the same matrix as Rails, so 6.1, 7.0 and 7.1

[JonRowe]

Closing in favour of #2706