Update repositories.txt

added 
https://github.com/drmpf/RTC_NTP_replacement

Author: drmpf

repositories.txt

@@ -1,5 +1,6 @@
 https://github.com/austin207/ArduinoCalculus.git
 https://github.com/salim-mrw/USB-Rubber
+https://github.com/drmpf/RTC_NTP_replacement
 https://github.com/salernosimone/espkit-arduino
 https://github.com/salernosimone/tensorflow-runtime-universal-arduino
 https://github.com/hanzeelvilla/MyLedIO