MP Select Mini 3mm Y-Axis Spacer

This is 3mm spacer to attach to the carriage of the MP Select Mini (verified on the v2) to trigger the y axis endstop with the nozzle farther back. This is needed if the nozzle head is no longer sitting over the build surface (such as when the hotend has been replaced with an authentic e3d v6).

I redesigned seagas' original spacer to be more stable in the x and z axes. Their spacer originally relied on friction to keep the piece from falling or moving around the carriage face. My design moves