Update repositories.txt added TamsinRose/SimpleCounter (#7305)

Added https://github.com/TamsinRose/SimpleCounter

Author: TamsinRose

repositories.txt

@@ -8571,6 +8571,7 @@ https://github.com/Bridgetek/EVE5-Arduino-Dev
 https://github.com/Bridgetek/EVE1-Arduino-Dev
 https://github.com/Bridgetek/EVE2-Arduino-Dev
 https://github.com/Bridgetek/EVE2-2-Arduino-Dev
+https://github.com/TamsinRose/SimpleCounter
 https://github.com/TamsinRose/CANMessage
 https://github.com/stm32duino/X-NUCLEO-IKS5A1
 https://github.com/fermeridamagni/arduino-minimal-ultrasonic