Actually use the library

ampel-firmware/co2_sensor.cpp

@@ -21,7 +21,7 @@ namespace config {
 #  include "src/lib/Esp8266EdgeSoftwareSerial/MySoftwareSerial.h"
 #  define S8_RX_PIN 13         // GPIO13, a.k.a. D7, connected to S8 Tx pin.
 #  define S8_TX_PIN 15         // GPIO15, a.k.a. D8, connected to S8 Rx pin.
-SoftwareSerial S8_serial(S8_RX_PIN, S8_TX_PIN);
+MySoftwareSerial S8_serial(S8_RX_PIN, S8_TX_PIN);
 #endif
 #if defined(ESP32)
 // GPIO16 connected to S8 Tx pin.