Fix casting bug

ampel-firmware/src/lib/NTPClient/NTPClient.cpp

@@ -251,7 +251,7 @@ void NTPClient::getFormattedDate(char *formatted_date, unsigned long secs) {
 
   char formatted_time[9];
   this->getFormattedTime(formatted_time, secs);
-  snprintf(formatted_date, 23, "%4d-%02d-%02lu %s%+03d", year, month, rawTime, formatted_time, (int8_t) this->_timeOffset / 3600);
+  snprintf(formatted_date, 23, "%4d-%02d-%02lu %s%+03d", year, month, rawTime, formatted_time, (int8_t) (this->_timeOffset / 3600));
 }
 
 void NTPClient::setEpochTime(unsigned long secs) {