fix: assert failed in example uart_async_rxtxtasks

examples/peripherals/uart/uart_async_rxtxtasks/main/uart_async_rxtxtasks_main.c

@@ -72,6 +72,6 @@ static void rx_task(void *arg)
 void app_main(void)
 {
     init();
-    xTaskCreate(rx_task, "uart_rx_task", 1024 * 2, NULL, configMAX_PRIORITIES, NULL);
-    xTaskCreate(tx_task, "uart_tx_task", 1024 * 2, NULL, configMAX_PRIORITIES - 1, NULL);
+    xTaskCreate(rx_task, "uart_rx_task", 1024 * 2, NULL, configMAX_PRIORITIES - 1, NULL);
+    xTaskCreate(tx_task, "uart_tx_task", 1024 * 2, NULL, configMAX_PRIORITIES - 2, NULL);
 }