There has been a pretty trivial issue on this package open on Github since February: Support hashable == 1.5 · Issue #11 · kapralVV/Unique · GitHub
The maintainer is Ukrainian, and unfortunately may have been caught up in the Ukraine/Russia conflict.
I emailed the maintainer directly earlier today. If maintainership (after the requisite delay) of this package does occur, I was hoping the maintainership could be transferred to Haskell GitHub Trust · GitHub . I am a member of that group and I will maintain it there.