Change terminfo update logic, and update
Using the tagged releases in the ncurses repository isn't actually a
good idea, since it fails to capture the patch releases made
subsequently.
Instead, we switch to grabbing the latest version and recording which
patch release it is. Normally, there would be a danger of grabbing
un-released changes, however this doesn't seem like an actual risk in
this case given how the ncurses repo seems to operate.
