flake.lock: Update (#4440)

Flake lock file updates:

• Updated input 'devenv':
    'github:cachix/devenv/d74232153d60ccdeba6f41eec8ce8b2be0b33ac6?narHash=sha256-vzMpFBValKbheQQ5x5op7/hBjn0omn3CDyiPUghJl1w%3D' (2024-12-06)
  → 'github:cachix/devenv/f81cf7dc4cbfa46de11618af94e5983c5e600d8c?narHash=sha256-RfNqLS5f9s3aiRZIOjSbM8Vz7x2dT/7zwJhyt9TLEmE%3D' (2024-12-19)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/4dc2fc4e62dbf62b84132fe526356fbac7b03541?narHash=sha256-FillH0qdWDt/nlO6ED7h4cmN%2BG9uXwGjwmCnHs0QVYM%3D' (2024-12-05)
  → 'github:NixOS/nixpkgs/b47fd6fa00c6afca88b8ee46cfdb00e104f50bca?narHash=sha256-nbG9TijTMcfr%2Bau7ZVbKpAhMJzzE2nQBYmRvSdXUD8g%3D' (2024-12-19)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/50862ba6a8a0255b87377b9d2d4565e96f29b410?narHash=sha256-qKL3vjO%2BIXFQ0nTinFDqNq/sbbnnS5bMI1y0xX215fU%3D' (2024-12-05)
  → 'github:numtide/treefmt-nix/65712f5af67234dad91a5a4baee986a8b62dbf8f?narHash=sha256-MMi74%2BWckoyEWBRcg/oaGRvXC9BVVxDZNRMpL%2B72wBI%3D' (2024-12-20)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>