Log Message:
libuv: updated to 1.20.3

v1.20.3:
* win: add Windows XP support to uv_if_indextoname()
* win: fix `'floor' undefined` compiler warning
* win, pipe: stop read for overlapped pipe
* build: fix utf-8 name of copyright holder
* zos: initialize pollfd revents
* zos,doc: add system V message queue note
* linux: don't use uv__nonblock_ioctl() on sparc