It seems like there is a “hanging” package in the Manifest.toml:
[[Dierckx]]
deps = ["BinaryProvider", "Libdl", "Random", "Test"]
git-tree-sha1 = "27a74763c20938a814da26f31a9e8408d16fec44"
uuid = "39dd38d3-220a-591b-8e3c-4c3a8c710a94"
version = "0.4.1"
The project doesn’t have that as a dependency and no other dependencies depend on it. Pkg should never have emitted such a Manifest and seems to get confused right now.
Perhaps try remove that entry.