Merge branch 'winh-goto-board-dropdown' into 'master'

Make go to issue board dropdown style consistent

See merge request !2641

app/assets/stylesheets/pages/boards.scss

@@ -707,6 +707,8 @@
 }
 
 .boards-switcher {
+  @include new-style-dropdown;
+
   padding-right: 10px;
 }