Merge branch 'sl-qa-staging-66-quarantine-failing-spec' into 'master'

Quarantine failing "rebase_merge_request_spec.rb"

See merge request gitlab-org/gitlab-ce!30933

qa/qa/specs/features/browser_ui/3_create/merge_request/rebase_merge_request_spec.rb

 # frozen_string_literal: true
 
 module QA
-  context 'Create' do
+  # Failure issue: https://gitlab.com/gitlab-org/quality/staging/issues/66
+  context 'Create', :quarantine do
     describe 'Merge request rebasing' do
       it 'user rebases source branch of merge request' do
         Runtime::Browser.visit(:gitlab, Page::Main::Login)