Now it's slightly under 25×20 mm, instead of slightly under 25×21 mm.

The new USB connector footprints have been merged into the KiCad library
now, so I can use them from there instead of from my own fork.

This bumps the version number to v1.1.  This version is not complete
yet; I plan to make the board a bit smaller before I call the next
version "done".

Since I plan on getting these made at OSH Park, I shouldn't use
footprints with plated slots.  Now I'm using the CircularHoles
variant of the USB Type-C connector footprint, which is more
OSH-Park-friendly.

This may mean that I need to make a minor board revision after the
footprints are merged.  Not that I mind terribly.