Ender 3 filament runout sensor with 2020 extruded aluminum mount

This is a remix of [markvanhaze](https://www.thingiverse.com/markvanhaze/about)'s [Ender 3 filament runout sensor](https://www.thingiverse.com/thing:3411145). I really liked the part and I had the switches on hand. However, I needed it to mount on top of my printer and attach to the 2020 extruded aluminum bar. So I remixed one of the parts to have a slide on mount for 2020 extruded aluminum.

I printed it at 15% infill but you can go higher if you think you need the strength.