Add HC4067 library 16 channel multiplexer (#2415)

Author: RobTillaart

repositories.txt

@@ -3553,6 +3553,7 @@ https://github.com/RobTillaart/FunctionGenerator
 https://github.com/RobTillaart/GAMMA
 https://github.com/RobTillaart/GST
 https://github.com/RobTillaart/GY521
+https://github.com/RobTillaart/HC4067
 https://github.com/RobTillaart/HeartBeat
 https://github.com/RobTillaart/Histogram
 https://github.com/RobTillaart/HMC6352