Merge branch 'make-GitLab-Gold-button-more-cta' into 'master'

Make GitLab.com free trial button primary

See merge request gitlab-org/gitlab-ee!7231

ee/app/views/shared/billings/_billing_plan_header.html.haml

@@ -23,4 +23,4 @@
     = render 'shared/billings/trial_status', namespace: namespace
 
   - if namespace.eligible_for_trial?
-    %p= link_to 'Start your free trial', new_gitlab_com_trial_url, class: 'btn btn-primary btn-inverted'
+    %p= link_to 'Start your free trial', new_gitlab_com_trial_url, class: 'btn btn-primary'