Fix rubocop CI - Githubissues

Fix rubocop workflow and rubocop-challenger workflow.

gemfiles/Gemfile.rails50 is missing. see https://github.com/Apipie/apipie-rails/actions/runs/7762735936/job/21173684766
set RUBY_VERSION env on rubocop and rubocop-challenger workflow because Ruby 3.2.3 released.
Skipped 7bc8e18 because the expected values for the tests have changed, causing the tests to fail.

Apipie / apipie-rails