Fix OpenStruct use in license_spec

.rubocop_todo/style/open_struct_use.yml

@@ -2,7 +2,6 @@
 Style/OpenStructUse:
   Exclude:
   - app/helpers/application_settings_helper.rb
-  - ee/spec/db/production/license_spec.rb
   - ee/spec/features/projects/new_project_spec.rb
   - ee/spec/finders/template_finder_spec.rb
   - ee/spec/graphql/ee/resolvers/board_lists_resolver_spec.rb

ee/spec/db/production/license_spec.rb

@@ -5,7 +5,7 @@ RSpec.describe 'Automated License Installation' do
   subject { load Rails.root.join('ee', 'db', 'fixtures', 'production', '010_license.rb') }
 
   it 'executes the gitlab:license:load task' do
-    expect(Rake::Task).to receive(:[]).with('gitlab:license:load').and_return(OpenStruct.new(invoke: true))
+    expect(Rake::Task).to receive(:[]).with('gitlab:license:load').and_return(double('license', invoke: true))
 
     subject
   end