Nuna Triv Adapter for Nuna Mixx Child Tray v2

Adapted the design by Ecas32 to improve some aspects of the Nuna Triv adaptor to make it better at rough handling.

• Thickened the walls
• Remove slots
• Make model printable without supports
• Added screw hole for M2 bolt as the tip that connects to the stroller. This greatly increases the strength of the adaptor.

The M2 bolt should be a button head at least 10mm long but can be any length up to around 25mm. A socket head will work too, it just won't 'snap' into the stroller when you push the adaptor in (you need to manually press the button on the stroller).