flake.lock: Update (#270)

Flake lock file updates:

• Updated input 'fenix':
    'github:nix-community/fenix/8f14b37d4ad9eafd33315ba67faded5c1e1a1044?narHash=sha256-W68/drb51fBhOl/BMOoRlI%2B7qxeoNWGmCZwAyuXVlQY%3D' (2024-09-14)
  → 'github:nix-community/fenix/18eefba7fd0bf03e115785948758a44125a9fd68?narHash=sha256-v3r7yJY8YE4HAzD5DXOxLkzj8YZKQ0xuccp9yppGW1U%3D' (2024-09-21)
• Updated input 'fenix/nixpkgs':
    'github:nixos/nixpkgs/4f807e8940284ad7925ebd0a0993d2a1791acb2f?narHash=sha256-IiA3jfbR7K/B5%2B9byVi9BZGWTD4VSbWe8VLpp9B/iYk%3D' (2024-09-11)
  → 'github:nixos/nixpkgs/c04d5652cfa9742b1d519688f65d1bbccea9eb7e?narHash=sha256-PmUr/2GQGvFTIJ6/Tvsins7Q43KTMvMFhvG6oaYK%2BWk%3D' (2024-09-19)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/4221354a8fe90ea8218d3757d14735eac08d3e81?narHash=sha256-0Cb2bK2eyZ1njSX3593USMlcrj94VZprNN1/HllIfgw%3D' (2024-09-13)
  → 'github:rust-lang/rust-analyzer/94b526fc86eaa0e90fb4d54a5ba6313aa1e9b269?narHash=sha256-nCmG4NJpwI0IoIlYlwtDwVA49yuspA2E6OhfCOmiArQ%3D' (2024-09-15)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/4f807e8940284ad7925ebd0a0993d2a1791acb2f?narHash=sha256-IiA3jfbR7K/B5%2B9byVi9BZGWTD4VSbWe8VLpp9B/iYk%3D' (2024-09-11)
  → 'github:NixOS/nixpkgs/c04d5652cfa9742b1d519688f65d1bbccea9eb7e?narHash=sha256-PmUr/2GQGvFTIJ6/Tvsins7Q43KTMvMFhvG6oaYK%2BWk%3D' (2024-09-19)