Ensure the project has a repository in spec/features/merge_request/user_sees_breadcrumb_links_spec.rb

This backport a fix that was made in https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7240
since the spec would fail there (and not in CE).

Signed-off-by: Rémy Coutable <remy@rymai.me>

spec/features/merge_request/user_sees_breadcrumb_links_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe 'New merge request breadcrumbs' do
-  let(:project) { create(:project) }
+  let(:project) { create(:project, :repository) }
   let(:user)    { project.creator }
 
   before do