flake.lock: Update

Flake lock file updates:

• Updated input 'dream2nix':
    'github:nix-community/dream2nix/400032c6303f82b07a09c9784ab5569a51544987?narHash=sha256-4vkxrZnHulJ8r6lewSr7oHjy0le66CxBRSgGr8WR3qg%3D' (2024-04-09)
  → 'github:nix-community/dream2nix/a77512d037fe3a4f17bc79a615a56f2c785cab89?narHash=sha256-dKu6KHj/DG3FhEq1MXtRswqGrFW2jGqrkzlbiAlzFEc%3D' (2024-04-21)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/a76c4553d7e741e17f289224eda135423de0491d?narHash=sha256-WwjUkWsjlU8iUImbivlYxNyMB1L5YVqE8QotQdL9jWc%3D' (2024-04-09)
  → 'github:NixOS/nixpkgs/f2d7a289c5a5ece8521dd082b81ac7e4a57c2c5c?narHash=sha256-Yd8KuOBpZ0Slau/NxFhMPJI0gBxeax0vq/FD0rqKwuQ%3D' (2024-04-21)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/e7354bb9e5f68b2074e272fd5f5ac3f4848860ba?narHash=sha256-FIAlt8mbPUs8jRuh6xpFtYzDsyHzmiLNPcen8HwvD00%3D' (2024-04-09)
  → 'github:oxalica/rust-overlay/a520e9870c46a0d0af3745a0b707dbf14b66f72c?narHash=sha256-IXwXOTN0GtMyLbtOy0qUNdfdnXIA8p4LbyKxBShS44Q%3D' (2024-04-21)
• Updated input 'sops-nix':
    'github:Mic92/sops-nix/538c114cfdf1f0458f507087b1dcf018ce1c0c4c?narHash=sha256-a4hbls4vlLRMciv62YrYT/Xs/3Cubce8WFHPUDWwzf8%3D' (2024-04-08)
  → 'github:Mic92/sops-nix/09f1bc8ba3277c0f052f7887ec92721501541938?narHash=sha256-4BvlfPfyUmB1U0r/oOF6jGEW/pG59c5yv6PJwgucTNM%3D' (2024-04-21)
• Updated input 'sops-nix/nixpkgs-stable':
    'github:NixOS/nixpkgs/e38d7cb66ea4f7a0eb6681920615dfcc30fc2920?narHash=sha256-g0whLLwRvgO2FsyhY8fNk%2BTWenS3jg5UdlWL4uqgFeo%3D' (2024-04-06)
  → 'github:NixOS/nixpkgs/74574c38577914733b4f7a775dd77d24245081dd?narHash=sha256-q7APLfB6FmmSMI1Su5ihW9IwntBsk2hWNXh8XtSdSIk%3D' (2024-04-20)