build liblangtag with updated IANA language-subtag-registry

... as downloaded from
https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry

Change-Id: I7aee9c6e42aabc9e023ab9a2ec3880dbde940396
Reviewed-on: https://gerrit.libreoffice.org/8919
Tested-by: LibreOffice gerrit bot <gerrit@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>