Allow Rails 8.0

[theodorton]

We're unable to test our project with edge Rails at the moment as route_translator doesn't officially support anything newer than 7.1 and the next version of Rails will be 8.0.

Ran the existing test suite against edge and they all seem to pass.

[coveralls]

coverage: 100.0%. remained the same
when pulling 3426d67 on Skalar:rails-8-0
into d5eddc2 on enriclluelles:master.

[tagliala]

Hi! Thanks for this PR

Can you please:

1. Rebase from master
2. Use 8.0 instead of 8.1. 8.0 will work for all the pre-release versions of Rails 8. Since Route Translator uses some Rails internals, we can't guarantee that it will be compatible with 8.0 stable until 8.0 will be released

[theodorton]

@tagliala thanks for the quick review :) I've rebased and pushed the correction you suggested.

[tagliala]

Thanks, v14.1.2 pushed to rubygems