Use specify with empty message block

https://github.com/rubocop-hq/rspec-style-guide#it-and-specify

ee/spec/models/ci/build_spec.rb

@@ -41,7 +41,7 @@ describe Ci::Build do
         job.runner = create(:ci_runner, :instance)
       end
 
-      it do
+      specify do
         expect(job.project).to receive(:shared_runners_minutes_limit_enabled?)
           .and_return(true)