Upgrade to Rails 8

[nhomenda]

This draft PR is a starting point for Rails 8 support. It has gemspec overrides to use core component branches that allow Rails 8. All of the test apps build and run successfully at Rails 8 with those overrides and a handful of initial fixes.

Currently, the gemspec uses a named branch (rails-8) in core components; this was done so that the test apps will build/run, which will enable specs to be worked on in parallel with core component updates.

Core components are currently awaiting releases so that the aforementioned overrides can be undone. So full Rails 8 compatibility should be possible by merging/releasing per the following in order:

PR approvals/merges:

• Adding support for Rails 8.1 hydra-head#564
• Prepare for 13.2.0 release hydra-head#565
• Support for Rails 8 hydra-derivatives#266
• Bump to 4.1 and prepare release hydra-derivatives#267
• Adding support for Rails 8 hydra-works#399
• Prepare for 2.3.0 release hydra-works#400
• Adding support for Rails 8 hydra-editor#227
• Prepare for 7.1.0 release hydra-editor#229

Gem releases:

• hydra-head 13.2
• hydra-derivatives 4.1
• hydra-works
• hydra-editor

[randalldfloyd]

Status as of 12-4-25:

Core components with direct Rails version constraints have been upgraded to Rails 8 and new versions released. The Hyrax rails-8 branch now uses those gems and has a PR in draft status at #7233 .

A large number of test failures seem to have something do with not being able to set things like indexer on classes inheriting from ActiveFedora::Base and including include Hyrax::WorkBehavior, but not sure yet why.

Here's the correct behavior in Hyrax on Rails 7.2:

Loading development environment (Rails 7.2.3)
...
class EssentialWork < ActiveFedora::Base
   include Hyrax::WorkBehavior
end

EssentialWork.indexer
=> Hyrax::WorkIndexer

klass = Class.new
=> #<Class:0x00007f466d598d40>

EssentialWork.indexer = klass
=> #<Class:0x00007f466d598d40>

EssentialWork.indexer
=> #<Class:0x00007f466d598d40>

And then on Hyrax at Rails 8:

Loading development environment (Rails 8.0.4)

class EssentialWork < ActiveFedora::Base
   include Hyrax::WorkBehavior
end

EssentialWork.indexer
=> Hydra::PCDM::ObjectIndexer

klass = Class.new
=> #<Class:0x00007f0ac1a82e60>

EssentialWork.indexer = klass
=> #<Class:0x00007f0ac1a82e60>

EssentialWork.indexer
=> Hydra::PCDM::ObjectIndexer