When I run cargo-upgrade upgrade I get:

Error: The repo at path /home/gabor/.cargo/registry/index/github.com-1ecc6299db9ec823 is unusable
due to having an invalid HEAD reference: reference 'refs/heads/main' not found; class=Reference (4);
code=NotFound (-3)

Apparently this was caused by me Ctrl-C-in a previous run of cargo-upgrade upgrade that seemed to have been stuck (not showing anything for more than a minute) After removing that folder and running cargo-upgrade upgrade again (and Ctrl-C-ing again) I get the same error.