devel/jujutsu: upgrade to version 0.17.1

Compared to version 0.16.0, this version contains a number of fixes
and improvements.

See the release notes at

https://github.com/martinvonz/jj/releases/tag/v0.17.0

for details.

Version 0.17.1 speeds up "jj status" by no longer scanning through
the entire history to look for ancestors with conflicts.