It's a USB Type-C connector just like the one used in v0.1 and v0.2, but
with only SMT pins (except the fixing pins, of course).  They're
slightly cheaper and probably nicer for automated assembly, but
impossible to hand-solder.  That's okay though: where we're going, we
don't need hand-solderability.

Google likes the name better this way.  Plus, it provides clear naming
for possible future PD Buddy products.

0 Ω resistors are cheap, and switches are expensive.  It would be nice
to be able to save the price of a switch, since it's not really
necessary anyway.  I can program these by SWD, after all.

I added a 0 Ω resistor, R11, to pull the BOOT pin to ground in lieu of
having SW1 installed to do the same job.

I had the source and drain reversed—whoops.  After fixing it with an
X-Acto knife and some point-to-point wiring, I've updated the schematic
and PCB files accordingly.

THIS ALSO MARKS THE BEGINNING OF DEVELOPMENT OF THE NEXT BOARD REVISION.

Tested to probably not blow anything up if assembled properly!