Bump Unicode version and data to 15.1.0

With this commit we just add the updated Unicode data. Given the Unicode
consortium, again, fiddled with their algorithms it takes a few
subsequent commits to fully support Unicode 15.1.0. Unicode 16.0,
scheduled to be released this month, should be a simple corollary; let's
see...

Signed-off-by: Laslo Hunhold <dev@frign.de>