Updated models to include Raspberry Pi Pico

Author: slouchd

README.md

@@ -34,6 +34,7 @@ The complete collection of (consumer) Raspberry Pi models consist of:
 - [Raspberry Pi 3, Model A+](https://www.raspberrypi.org/products/raspberry-pi-3-model-a-plus/) (November, 2018)
 - [Raspberry Pi 4, Model B](https://www.raspberrypi.org/products/raspberry-pi-4-model-b/) (June, 2019)
 - [Raspberry Pi 400](https://www.raspberrypi.org/products/raspberry-pi-400/) (November, 2020)
+- [Raspberry Pi Pico](https://www.raspberrypi.org/products/raspberry-pi-pico/) (January, 2021)
 
 ## OS Images