Please add support for the nRF52840 dongle pca10059.
Documentation here: https://www.nordicsemi.com/eng/Products/nRF52840-Dongle

I'm willing to do it, but I'm new to Micropython, so I don't have all the information I need.
Is there already an implementation that has Repl over native USB?
That would be the biggest change.
Changing the pin assignments from pca10056 shouldn't be too complicated.