devel/dorst: Update 0.19.5 => 0.20.0
While here, remove desktop-file-utils since
the .desktop file doesn't contain MimeType entry.
Changelog:
https://github.com/charlesrocket/dorst/releases/tag/v0.20.0
PR: 294477
Reported by: charlesrocket <slowdive@me.com> (maintainer)
Approved by: osa (mentor)