Compatibility with jsonapi-resources@0.9.9

[krasnoukhov]

Previous upgrade was in #98

Spec change reflects new JR behavior of not including relationship links in case its routes were not defined:

jsonapi-utils/spec/test_app.rb

Lines 61 to 64 in 36c7601

	jsonapi_resources :users do
	jsonapi_links :profile
	jsonapi_related_resources :posts
	end

It does not call jsonapi_related_resource :profile within the block.

[tiagopog]

Thanks for contributing @krasnoukhov 🎉