Add Serial logging to simple blink sketch

src/main.cpp

@@ -1,15 +1,19 @@
 #include <Arduino.h>
 
 void setup() {
-  // put your setup code here, to run once:
+  Serial.begin(9600);
+  while (!Serial) {
+    delay(100);
+  }
+  Serial.println("Starting");
   pinMode(2,OUTPUT);
-  
 }
 
 void loop() {
   digitalWrite(2,HIGH);
+  Serial.println("ON");
   sleep(1);
   digitalWrite(2,LOW);
+  Serial.println("OFF");
   sleep(1);
-  
 }