Document how to do an update, fix the bit-rot that had crept into
main.cpp since last it was compiled, correct the qt_attribution.json
to use the actual version number of UCD (its Revision number) instead
of the (admittedly correlated) Unicode release number. Updated to
Release 22 (which came with Unicode 11.0.0) in the process; but this
doesn't change our actual qunicodetables.cpp (so is incidental).
Task-number: QTBUG-71281
Change-Id: Ieb7a6e1a4d49f639993f76ff82c8f12a572db3c3
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
d38f635355