Log Message:
utf8proc: update to 2.3.0.

## Version 2.3 ##

2019-03-30

- Unicode 12 support ([#148]).

- New function `utf8proc_unicode_version` to return the supported Unicode \ 
version ([#151]).

- Simpler character-width computation that no longer uses GNU Unifont metrics: \ 
East-Asian wide
  characters have width 2, and all other printable characters have width 1 ([#150]).

- Fix `CHARBOUND` option for `utf8proc_map` to preserve U+FFFE and U+FFFF \ 
non-characters ([#149]).

- Various build-system improvements ([#141], [#142], [#147]).