MMU3 Spool Holder Wheel Upgrades

I had to replace the wheels on the MMU3 spool holders, those plastic ones weren't smooth enough and I repeatedly had spools being kicked out, this is much better now.

For each spool holder you'll need 4x started 20mm skateboard bearings, 4x MMU3 Spool Holder Tyre printed in TPU and 8x MMU3 Spool Holder Spindle printed in PLA.

I've included the STL's and the gcode for 2x tyres and 4x spindles.