flake.lock: Update (#305)

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/4f807e8940284ad7925ebd0a0993d2a1791acb2f?narHash=sha256-IiA3jfbR7K/B5%2B9byVi9BZGWTD4VSbWe8VLpp9B/iYk%3D' (2024-09-11)
  → 'github:nixos/nixpkgs/345c263f2f53a3710abe117f28a5cb86d0ba4059?narHash=sha256-sjiGsMh%2B1cWXb53Tecsm4skyFNag33GPbVgCdfj3n9I%3D' (2024-09-13)
```

### Running GitHub Actions on this PR

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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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