flake.inputs: automatic update

Flake lock file updates:

• Updated input 'nix-index-database':
    'github:Mic92/nix-index-database/642275444c5a9defce57219c944b3179bf2adaa9?narHash=sha256-hwX53i24KyWzp2nWpQsn8lfGQNCP0JoW/bvQmcR1DPY%3D' (2024-09-08)
  → 'github:Mic92/nix-index-database/c1b0fa0bec5478185eae2fd3f39b9e906fc83995?narHash=sha256-1AX7MyYzP7sNgZiGF8jwehCCI75y2kBGwACeryJs%2ByE%3D' (2024-09-16)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/68e7dce0a6532e876980764167ad158174402c6f?narHash=sha256-ZPzhebbWBOr0zRWW10FfqfbJlan3G96/h3uqhiFqmwg%3D' (2024-09-07)
  → 'github:NixOS/nixpkgs/8f7492cce28977fbf8bd12c72af08b1f6c7c3e49?narHash=sha256-RuVXUwcYwaUeks6h3OLrEmg14z9aFXdWppTWPMTwdQw%3D' (2024-09-14)
• Updated input 'unstable':
    'github:NixOS/nixpkgs/add0443ee587a0c44f22793b8c8649a0dbc3bb00?narHash=sha256-0Kq2MkQ/sQX1rhWJ/ySBBQlBJBUK8mPMDcuDhhdBkSU%3D' (2024-09-08)
  → 'github:NixOS/nixpkgs/76d7694a3f681b0b750c01783df5d2177ef39fe7?narHash=sha256-EpiSl9nSINTmIW6MG6CulGwNAa6sHrBt8gQdyHUXzR4%3D' (2024-09-15)