hotfix for gossip test flaking

gossip/src/cluster_info.rs

@@ -3752,6 +3752,7 @@ mod tests {
             let mut node = cluster_info.my_contact_info.write().unwrap();
             node.set_shred_version(42);
         }
+        std::thread::sleep(Duration::from_millis(1));
         cluster_info.refresh_my_gossip_contact_info();
         cluster_info.flush_push_queue();
         // Should now include both epoch slots.