flake.lock: Update (#1616)

Automated changes by the
[update-flake-lock](https://github.com/DeterminateSystems/update-flake-lock)
GitHub Action.

```
Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/d3c42f187194c26d9f0309a8ecc469d6c878ce33?narHash=sha256-cHar1vqHOOyC7f1%2BtVycPoWTfKIaqkoe1Q6TnKzuti4%3D' (2024-12-17)
  → 'github:NixOS/nixpkgs/634fd46801442d760e09493a794c4f15db2d0cbb?narHash=sha256-NYVcA06%2BblsLG6wpAbSPTCyLvxD/92Hy4vlY9WxFI1M%3D' (2024-12-27)
• Updated input 'released-nix-unstable':
    'github:nixos/nix/f72752c0dc6547b1568a9ef46deba875e38fada2?narHash=sha256-NyQErDMVmRB0xPLLylZcw1mIBH3d8bSue8Fp%2BvRBLso%3D' (2024-12-20)
  → 'github:nixos/nix/8a3fc27f1b63a08ac983ee46435a56cf49ebaf4a?narHash=sha256-JfQXQL0MysQSfvbw7xHto9YbqZ1VQLFgus%2Bc4KYt6xg%3D' (2024-12-28)
• Updated input 'released-nixpkgs-stable':
    'github:NixOS/nixpkgs/1c6e20d41d6a9c1d737945962160e8571df55daa?narHash=sha256-GIMyMt1pkkoXdCq9un859bX6YQZ/iYtukb9R5luazLM%3D' (2024-12-20)
  → 'github:NixOS/nixpkgs/d49da4c08359e3c39c4e27c74ac7ac9b70085966?narHash=sha256-MgdXpeX2GuJbtlBrH9EdsUeWl/yXEubyvxM1G%2ByO4Ak%3D' (2024-12-27)
• Updated input 'released-nixpkgs-unstable':
    'github:NixOS/nixpkgs/d3c42f187194c26d9f0309a8ecc469d6c878ce33?narHash=sha256-cHar1vqHOOyC7f1%2BtVycPoWTfKIaqkoe1Q6TnKzuti4%3D' (2024-12-17)
  → 'github:NixOS/nixpkgs/634fd46801442d760e09493a794c4f15db2d0cbb?narHash=sha256-NYVcA06%2BblsLG6wpAbSPTCyLvxD/92Hy4vlY9WxFI1M%3D' (2024-12-27)
```

### Running GitHub Actions on this PR

GitHub Actions will not run workflows on pull requests which are opened
by a GitHub Action.

To run GitHub Actions workflows on this PR, run:

```sh
git branch -D update_flake_lock_action
git fetch origin
git checkout update_flake_lock_action
git commit --amend --no-edit
git push origin update_flake_lock_action --force
```

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