Add Arduino Nano w/ New Bootloader target

Since 2018, Arduino Nanos and clones are sold with a new bootloader, which
requires programming at 115200 baud instead of the 57600 baud required
by the old one.

targets/arduino-nano-new.json

@@ -0,0 +1,4 @@
+{
+	"inherits": ["arduino-nano"],
+	"flash-command": "avrdude -c arduino -p atmega328p -b 115200 -P {port} -U flash:w:{hex}:i"
+}