Use keyword arguments in tests

Raisl 5.1 removes support for non-keyword arguments in `#process`,
`#get`, `#post`, `#patch`, `#put`, `#delete`, and `#head` for the
`ActionDispatch::IntegrationTest` and `ActionController::TestCase`
classes. This means we have to add `params` everywhere in the controller
tests.

spec/controllers/admin/events_controller_spec.rb

@@ -17,7 +17,7 @@ describe Admin::EventsController do
     describe 'GET #show' do
       before :each do
         sign_in(organizer)
-        get :show, id: event_without_commercial.id, conference_id: conference.short_title
+        get :show, params: { id: event_without_commercial.id, conference_id: conference.short_title }
       end
 
       it 'assigns versions' do