Put the correct Unicode version number 11.0.0 into the generated files

In some places there was still the old Unicode version 10.0.0 in the files.

	* localedata/charmaps/UTF-8: Use correct Unicode version 11.0.0 in comment.
	* localedata/locales/i18n_ctype: Use correct Unicode version in comments
	and headers.
	* localedata/unicode-gen/utf8_gen.py: Add option to specify Unicode version
	* localedata/unicode-gen/Makefile: Use option to specify Unicode version
	for utf8_gen.py