flake.lock: Update (#719)

Flake lock file updates:

• Updated input 'fenix':
    'github:nix-community/fenix/89a969653519a0503027421999e3f3944e2184fe' (2023-10-14)
  → 'github:nix-community/fenix/595a9eed67a4bf54dfe3e5c3299362a695fef758' (2023-10-21)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/862693ff954660d169774c8ada4672fb96dabf36' (2023-10-13)
  → 'github:rust-lang/rust-analyzer/954fb1d673107f3de5cab9b06cb3d1a2323eb6e0' (2023-10-20)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/5e4c2ada4fcd54b99d56d7bd62f384511a7e2593' (2023-10-11)
  → 'github:NixOS/nixpkgs/7c9cc5a6e5d38010801741ac830a3f8fd667a7a0' (2023-10-19)
• Updated input 'nixpkgs-cross-overlay':
    'github:alekseysidorov/nixpkgs-cross-overlay/c7068e74690518c9c00dcccf907829f1c31de3e2' (2023-10-09)
  → 'github:alekseysidorov/nixpkgs-cross-overlay/27fb2bd7eb5a5e1064fe6961ee91e317c9a0fa68' (2023-10-21)
• Updated input 'nixpkgs-cross-overlay/nixpkgs':
    'github:NixOS/nixpkgs/87828a0e03d1418e848d3dd3f3014a632e4a4f64' (2023-10-06)
  → 'github:NixOS/nixpkgs/ca012a02bf8327be9e488546faecae5e05d7d749' (2023-10-16)
• Updated input 'nixpkgs-cross-overlay/rust-overlay':
    'github:oxalica/rust-overlay/6528a18a62d817200099c520b6eea7833ade9a9a' (2023-10-08)
  → 'github:oxalica/rust-overlay/679ea0878edc749f23516ea6d7ffa974c6304bf5' (2023-10-20)
• Updated input 'nixpkgs-cross-overlay/treefmt-nix':
    'github:numtide/treefmt-nix/720bd006d855b08e60664e4683ccddb7a9ff614a' (2023-09-27)
  → 'github:numtide/treefmt-nix/aae39f64f5ecbe89792d05eacea5cb241891292a' (2023-10-15)
• Updated input 'pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/42e1b6095ef80a51f79595d9951eb38e91c4e6ca' (2023-10-09)
  → 'github:cachix/pre-commit-hooks.nix/8cc349bfd082da8782b989cad2158c9ad5bd70fd' (2023-10-19)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/dce60ca7fca201014868c08a612edb73a998310f' (2023-10-14)
  → 'github:oxalica/rust-overlay/6e8e3332433847cd56186b1f6fc8c47603cf5b46' (2023-10-21)

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