Update jackpot3.md

added jackpot model file link

Author: V1EngineeringInc

docs/electronics/jackpot3.md

@@ -353,3 +353,5 @@ V0 - The initial release.
 This project is released under [GPL3](https://www.gnu.org/licenses/gpl-3.0.en.html)
 
 Here is an [EasyEDA link](https://u.easyeda.com/join?type=project&key=3cd4237e079f521e5dab17848f252ec5&inviter=077a66e731864c5cb238c7a4979f3b30) to the project that you can clone and work from.
+
+You can make a solid model from the EasyEDA link, or I made one [here](https://www.printables.com/model/1434650-jackpot3-box) in Onshape.