flake.lock: Update

Flake lock file updates:

• Updated input 'home-manager':
    'github:nix-community/home-manager/abdc82d930521448e47574b8ca1a0a450e861cca' (2023-12-15)
  → 'github:nix-community/home-manager/3bfaacf46133c037bb356193bd2f1765d9dc82c1' (2023-12-20)
• Updated input 'nix-index-database':
    'github:Mic92/nix-index-database/45d82e0a8b9dd6c5dd9da835ac0c072239af7785' (2023-12-11)
  → 'github:Mic92/nix-index-database/4605ccd764fac78b9e4b5b058698cb9f04430b91' (2023-12-18)
• Updated input 'nixos-unstable':
    'github:nixos/nixpkgs/a9bf124c46ef298113270b1f84a164865987a91c' (2023-12-11)
  → 'github:nixos/nixpkgs/54aac082a4d9bb5bbc5c4e899603abfb76a3f6d6' (2023-12-19)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/aa9d4729cbc99dabacb50e3994dcefb3ea0f7447' (2023-12-14)
  → 'github:nixos/nixpkgs/69973a9a20858b467dd936542c63554f3675e02d' (2023-12-20)
• Updated input 'stable':
    'github:nixos/nixpkgs/cf28ee258fd5f9a52de6b9865cdb93a1f96d09b7' (2023-12-12)
  → 'github:nixos/nixpkgs/d02ffbbe834b5599fc5f134e644e49397eb07188' (2023-12-18)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/d06b70e5163a903f19009c3f97770014787a080f' (2023-12-13)
  → 'github:numtide/treefmt-nix/2961375283668d867e64129c22af532de8e77734' (2023-12-19)