libuv: update to 1.23.0.

2018.08.18, Version 1.23.0 (Stable)

Changes since version 1.22.0:

* win,pipe: restore compatibility with the old IPC framing protocol (Bert
  Belder)

* fs: add uv_open_osfhandle (Bartosz Sosnowski)

* doc: update Visual C++ Build Tools URL (Michał Kozakiewicz)

* unix: loop starvation on successful write complete (jBarz)

* win: add uv__getnameinfo_work() error handling (A. Hauptmann)

* win: return UV_ENOMEM from uv_loop_init() (cjihrig)

* unix,win: add uv_os_{get,set}priority() (cjihrig)

* test: fix warning in test-tcp-open (Santiago Gimeno)

(wiz)