- Update to version 5.7.1
* This release contains fixes for the two regressions reported
with VCS_Info and prompt colour sequences.

- Update to version 5.7
* Support for 24-bit true color terminals has been added.
Hex triplets can be used when specifying colours for prompts
and line editor highlighting. On 88 and 256 colour terminals,
a new zsh/nearcolor module allows colours specified with hex
triplets to be matched against the nearest available colour.
* The zsh/datetime module's strftime builtin now accepts an
argument specifying the nanoseconds time component; both
arguments can be omitted to use the current time.