libfswatch README copyright looks stale

[mistermocha]

Uncertain if this is acceptable as I'm not a copyright lawyer, but...

The libfswatch README has a copyright date that ended in 2016, but the libfswatch code has been updated as recently as six months ago (2022). That copyright date, which is linked off the main fswatch README front page, suggested to me at first that the core library was possibly out of date and nearly drove me off of wanting to use this project since multiple OSX versions have been released since 2016.

I don't know what the correct reading should be for a copyright on a readme, but I figured I'd bring it up.