create a project to dim an LED using a potentiometer

[tanyafish]

We need instructions and code to dim an external LED using a potentiometer.

Needs:

• a description of what the code will do and how to wire up the LED and potentiometer, including warnings to avoid magic blue smoke
• a wiring diagram
• the code to control it, with clear comments to show what each piece of it does. If in doubt, overcomment!

[tanyafish]

Note: this can be done with a microbit or an arduino nano - make sure you check the equipment list in the main repository and only use physical items from there.

For microbit, use micropython and save as a .py file, and for the arduino use C++ and save as a .ino file.