Update YouTube URL

The link was an outdated one to https://www.youtube.com/watch?v=7RH-1pAbjvw
The correct link appears to be https://www.youtube.com/watch?v=tx54jkRC9ZY which is shortened as in the file.

docs/newbs_building_firmware_configurator.md

@@ -4,7 +4,7 @@ The [QMK Configurator](https://config.qmk.fm) is an online graphical user interf
 
 ?> **Please follow these steps in order.**
 
-Watch the [Video Tutorial](https://youtu.be/7RH-1pAbjvw)
+Watch the [Video Tutorial](https://youtu.be/tx54jkRC9ZY)
 
 The QMK Configurator works best with Chrome/Firefox.