[JDY08] Fixed incorrect variable name

examples/JDY08/JDY08.ino

@@ -22,11 +22,11 @@ void loop() {
   // JDY08 supports all methods of the Serial class
   // read data incoming from Serial port and write them to Bluetooth
   while (Serial.available() > 0) {
-    bluetooth.write(Serial.read());
+    ble.write(Serial.read());
   }
 
   // read data incoming from Bluetooth and write them to Serial port
   while (bluetooth.available() > 0) {
-    Serial.write(bluetooth.read());
+    Serial.write(ble.read());
   }
 }