Update repositories.txt (arduino#3150)

Please add this library to the Library Manager.
Best Regards

Author: cparata

repositories.txt

@@ -6089,3 +6089,4 @@ https://github.com/adafruit/Adafruit_TSC2046
 https://github.com/FacundoPumilla/MQ137
 https://github.com/JSC-electronics/acdu-support-library
 https://github.com/AlexRosito67/QUAD7SHIFT
+https://github.com/stm32duino/LIS2DUXS12