Update cabling.md

fix doc

Author: cp-bagerard

doc/cabling.md

@@ -3,7 +3,7 @@
 ## Steps
 
 Here is the electronic schema (built with Fritzing) showing how 1 button is wired. Basically:
-- Buttons are directly wired to the RaspberryPu GPIO pin
+- Buttons are directly wired to the RaspberryPi GPIO pin
 - The Buttons' LEDs have their (-) pin going through a ULN2003A transistor
 
 ![fritz_schema](fritz_schema.png)