Increase echo task stack size to 2*2048 for better performance.

espressif/esp-idf#14382
espressif/esp-idf#14381
Update echo task stack size to be twice the original value.

- Increase echo task stack size to 2*2048 for better performance.

uart_echo_rs485/main/rs485_example.c

@@ -39,7 +39,7 @@
 
 // Read packet timeout
 #define PACKET_READ_TICS        (100 / portTICK_PERIOD_MS)
-#define ECHO_TASK_STACK_SIZE    (2048)
+#define ECHO_TASK_STACK_SIZE    (2*2048)
 #define ECHO_TASK_PRIO          (10)
 #define ECHO_UART_PORT          (CONFIG_ECHO_UART_PORT_NUM)