Merge branch 'winh-merge-request-form-dropdowns-ee' into 'master'

Make merge request form dropdowns consistent

See merge request !2790

app/assets/stylesheets/pages/merge_requests.scss

@@ -797,3 +797,7 @@
     }
   }
 }
+
+.merge-request-form {
+  @include new-style-dropdown;
+}