Better pin for Universal Filament Spool Holder

This is a remplacement pin for "Universal_Filament_Spool_Holder" (https://www.thingiverse.com/thing:213371)

The original Pin, in my opinion, have two problems. This one:
- is less long (this one is 19mm between blocking ends)
- have mote robust end clip

**Edit**:

Since I changed to another design, [available here](https://www.thingiverse.com/thing:2796965)