integration: bump up wait leader timeout for slow CIs

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

integration/cluster.go

@@ -387,7 +387,7 @@ func (c *cluster) waitLeader(t *testing.T, membs []*member) int {
 
 	// ensure leader is up via linearizable get
 	for {
-		ctx, cancel := context.WithTimeout(context.Background(), 10*tickDuration)
+		ctx, cancel := context.WithTimeout(context.Background(), 10*tickDuration+time.Second)
 		_, err := kapi.Get(ctx, "0", &client.GetOptions{Quorum: true})
 		cancel()
 		if err == nil || strings.Contains(err.Error(), "Key not found") {