fix ArgumentError building routes on Rails 8.1

[SAY-5]

All Submissions:

• I've checked to ensure there aren't other open Pull Requests for the same update/change.
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• My submission passes all tests. (Please run the full test suite locally to cut down on noise from travis failures.)
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• I've added/updated tests for this change.

Bug fixes and Changes to Core Features:

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• I've provided test(s) that fails without the change.

Test Plan:

rake test needs a database and currently errors out on a booted-app requirement in rails/test_help that's unrelated to this change (reproduces the same way on master with Rails 7.2 and 8.1, so it looks like a separate pre-existing gap in test_helper.rb's Rails 8 support). To verify this fix directly I installed actionpack 7.2.2.2 and 8.1.3.1 side by side and drew routes with jsonapi_resources through a real ActionDispatch::Routing::RouteSet#draw, which is what test/unit/routing_ext_test.rb does. That test errors with the exact ArgumentError: wrong number of arguments (given 4, expected 3) from the issue when run against master, and passes on both Rails versions with this change.

Reviewer Checklist:

• Maintains compliance with JSON:API
• Adequate test coverage exists to prevent regressions

Fixes #1488

Rails 8.1 changed ActionDispatch::Routing::Mapper::Resource#initialize (and SingletonResource) to take only:/except: as keywords instead of a trailing positional options hash (rails/rails#53689). jsonapi_resource(s) still calls both with a plain positional hash, so drawing any route on Rails 8.1 raises ArgumentError: wrong number of arguments (given 4, expected 3) before the app boots. Passing options with ** instead of positionally works on both the old and the new signature.