devel/jujutsu: upgrade to 0.28.1

This upgrade contains the functional changes introduced in
version 0.28.0 and the fix for the security issue that had
been introduced in that version.

The dependency on libzstd.so has been removed.

See the release notes for a list of fixes and changes:

https://github.com/martinvonz/jj/releases/tag/v0.28.0
https://github.com/martinvonz/jj/releases/tag/v0.28.1

PR: 276648