Fix Gitlab::GrapeOpenapi.generate

Gitlab::GrapeOpenapi.generate passes 2 arguments to Gitlab::GrapeOpenapi::Generator#initialize, but that constructor only accepts one. This results in:

ArgumentError: wrong number of arguments (given 2, expected 0..1)

Steps to reproduce

1. Open bundle exec rails console
2. Run: spec = Gitlab::GrapeOpenapi.generate({ api_classes: [API::API] })

Current behavior

• Gitlab::GrapeOpenapi.generate(api_classes, options = {}) calls Generator.new(api_classes, options).generate (2 arguments)
• Generator#initialize(options = {}) only accepts 1 argument
• This causes an ArgumentError

Expected behavior

Gitlab::GrapeOpenapi.generate should work without raising an ArgumentError.

What needs to be done

Update Gitlab::GrapeOpenapi.generate to pass arguments correctly to Generator#initialize. The method should merge api_classes into the options hash before passing it to the constructor.

File: gems/gitlab-grape-openapi/lib/gitlab-grape-openapi.rb

Acceptance criteria

• Gitlab::GrapeOpenapi.generate({ api_classes: [API::API] }) executes without raising ArgumentError
• Existing tests pass
• The generated OpenAPI spec is correct