Add submission # 2891

#2891

Author: ArduinoBot

registry.txt

@@ -5988,3 +5988,4 @@ https://github.com/m5stack/M5CoreS3.git|Contributed|M5CoreS3
 https://github.com/deneyapkart/deneyap-servo-arduino-library.git|Contributed|Deneyap Servo
 https://github.com/hmz06967/SPI-FlashMem.git|Contributed|SPI-FlashMem
 https://github.com/hmz06967/OZGPS_NMEA.git|Contributed|OZGPS_NMEA
+https://github.com/wzwyz/Stringcalculater.git|Contributed|Stringcalculater