Update README.md

Author: wke67

megaavr/bootloaders/optiboot_dex/README.md

@@ -1,8 +1,10 @@
 The configure script generates a config_{MCU}.h file. It is called with arguments:
 - ./configure  MCU  LED_PIN  #LED_toggles  UART_TX_PIN  BAUDRATE
+
 For generating and flashing the boot loader use: 
 - make {MCU}.hex will include the config file and generate a bootloader{MCU}.hex file
 - make {MCU}.flash_d/ex will use avrdude (8.1) to flash the chip via updi
+
 Programming requires avrdude 8.1 or later. Download and extract it to the location used in Makefile.
 
 The configure script uses the header files that come with avr-gcc compiler. As ioavrxxYYzz.h appears to be generated, the comment lines of the USART PORTMUX are a reliable source for the USART pin mapping.