Flake doesn't evaluate

[L-as]

What Git revision are you using?

0acf18ea5c1c3bcb0a8aa93cefff3f831ff60981

What operating system are you using, and which version?

• [ ] Linux / Ubuntu
• [x] Linux / Other
• [ ] OSX
• [ ] Windows

Describe what the problem is?

$ nix build
warning: not writing modified lock file of flake 'git+file:///work/ogmios':
• Updated input 'customConfig':
    'path:./custom-config?narHash=sha256-NdBgwn6xJOM5j+T4ViTq+7FToInEbzvKcdOBpjQvILw='
  → 'path:./nix/custom-config?narHash=sha256-4wRvnnVtCrHE0puR4+%2f+qp4DoUboPuCbCe7GmWOGASA='
• Updated input 'nixpkgs':
    follows 'haskellNix/nixpkgs-2105'
  → follows 'haskellNix/nixpkgs-unstable'
error: 'outputs' at /nix/store/bpxvkyqnxf2k4m9srmdgglxqn7g79d8n-source/flake.nix:56:13 called without required argument 'flake-utils'

What should be the expected behavior?

It should build something.

[KtorZ]

Fixed with #148