Generalize the use of JSON_MSG_BUFFER (#1114)

* Generalize the use of JSON_MSG_BUFFER

instead of calculated buffer

main/ZsensorGPIOInput.ino

@@ -77,8 +77,7 @@ void MeasureGPIOInput() {
     if (reading != InputState) {
       InputState = reading;
       Log.trace(F("Creating GPIOInput buffer" CR));
-      const int JSON_MSG_CALC_BUFFER = JSON_OBJECT_SIZE(1);
-      StaticJsonDocument<JSON_MSG_CALC_BUFFER> jsonBuffer;
+      StaticJsonDocument<JSON_MSG_BUFFER> jsonBuffer;
       JsonObject GPIOdata = jsonBuffer.to<JsonObject>();
       if (InputState == HIGH) {
         GPIOdata["gpio"] = "HIGH";