flake.lock: Update

Flake lock file updates:

• Updated input 'flake-utils':
    'github:numtide/flake-utils/1ed9fb1935d260de5fe1c2f7ee0ebaae17ed2fa1' (2022-05-30)
  → 'github:numtide/flake-utils/7e2a3b3dfd9af950a856d66b0a7d01e3c18aa249' (2022-07-04)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/90cd5459a1fd707819b9a3fb9c852beaaac3b79a' (2022-06-11)
  → 'github:nixos/nixpkgs/e494a908e8895b9cba18e21d5fc83362f64b3f6a' (2022-07-24)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/e04a88d7f859ae9ec42267866bb68c1a741e6859' (2022-06-12)
  → 'github:oxalica/rust-overlay/ca940790dfceda8deada1a6c6ec32ecb9483f79f' (2022-07-24)
• Updated input 'rust-overlay/flake-utils':
    'github:numtide/flake-utils/bba5dcc8e0b20ab664967ad83d24d64cb64ec4f4' (2021-11-15)
  → 'github:numtide/flake-utils/bee6a7250dd1b01844a2de7e02e4df7d8a0a206c' (2022-06-24)
• Updated input 'rust-overlay/nixpkgs':
    'github:NixOS/nixpkgs/8afc4e543663ca0a6a4f496262cd05233737e732' (2021-11-21)
  → 'github:NixOS/nixpkgs/16de63fcc54e88b9a106a603038dd5dd2feb21eb' (2022-06-28)