Update RTC Library (Unix function)

`getUnixTime()` function contained a leftover debug print function. This PR removes it.

Author: karlsoderby

libraries/RTC/src/RTClock.cpp

@@ -347,7 +347,7 @@ int RTCTime::getMinutes()         { return minutes; }
 int RTCTime::getSeconds()         { return seconds; }
 DayOfWeek RTCTime::getDayOfWeek() { return day_of_week; }
 
-time_t RTCTime::getUnixTime()  { Serial.println(stime.tm_year);Serial.println(stime.tm_mon);Serial.println(stime.tm_mday);  return mktime ( (struct tm *)&stime ); }
+time_t RTCTime::getUnixTime()  { return mktime ( (struct tm *)&stime ); }
 struct tm RTCTime::getTmTime() { return (struct tm)stime; }
 
 /* -------------------------------------------------------------------------- */