fix: put deep sleep in loop since it does not seem to impact rtc ram

src/main.cpp

@@ -5,12 +5,12 @@ void setup() {
     delay(2000);
     
     loraInit();
+}
+
+void loop() {
     loraJoin();
     uint8_t payload[] = { 0x01, 0x02, 0x03 };
     loraSend(payload, sizeof(payload));
     Serial.flush();
     esp_deep_sleep(60000000);
-}
-
-void loop() {
 }