add DFRobot_DS323X library (#614)

Author: wxzed

repositories.txt

@@ -23,6 +23,7 @@ https://github.com/DFRobot/DFRobot_DF1201S
 https://github.com/DFRobot/DFRobot_URM13
 https://github.com/DFRobot/DFRobot_BMX160
 https://github.com/DFRobot/DFRobot_PAJ7620U2
+https://github.com/DFRobot/DFRobot_DS323X
 https://github.com/MajicDesigns/MD_OnePin
 https://github.com/cygig/DailyStruggleButton
 https://github.com/FTTechBrasil/FTTech-LoRaWAN