flake.lock: Update (#1500)

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/d603719ec6e294f034936c0d0dc06f689d91b6c3?narHash=sha256-k3JqJrkdoYwE3fHE6xGDY676AYmyh4U2Zw%2B0Bwe5DLU%3D' (2024-06-20)
  → 'github:NixOS/nixpkgs/9f4128e00b0ae8ec65918efeba59db998750ead6?narHash=sha256-rwz8NJZV%2B387rnWpTYcXaRNvzUSnnF9aHONoJIYmiUQ%3D' (2024-07-03)
• Updated input 'released-nix-stable':
    'github:nixos/nix/ba36959311e09bd798f7029c41e108d9d77c9ac0?narHash=sha256-cRCwRDxR8rEQQEvGjIH8g0krJd4ZFJrdgmPXkv65S/Y%3D' (2024-06-10)
  → 'github:nixos/nix/39735546f1f5eee0afa40c4778cf4ba0722b5926?narHash=sha256-NH1G4GGHXU4pnQWI9X/gs7r97GO0i4tJFjoaIxl0FaQ%3D' (2024-07-05)
• Updated input 'released-nix-unstable':
    'github:nixos/nix/1c131ec2b71fa7ad6fd285ed2a9fcc4cf616b3a6?narHash=sha256-SBioRAhjYMcoBpIGV%2BkdquRjlm8DRD2dv8N4RXM694U%3D' (2024-06-19)
  → 'github:nixos/nix/41b6c735eba1ca67e58a4c62507b404e5922157b?narHash=sha256-zA6IsI0OfJ1nRTYi0t1Jb4VM/LkpIvGLIdxkaVY/dCQ%3D' (2024-07-06)
• Updated input 'released-nixpkgs-stable':
    'github:NixOS/nixpkgs/dd457de7e08c6d06789b1f5b88fc9327f4d96309?narHash=sha256-wM9v2yIxClRYsGHut5vHICZTK7xdrUGfrLkXvSuv6s4%3D' (2024-06-19)
  → 'github:NixOS/nixpkgs/c0d0be00d4ecc4b51d2d6948e37466194c1e6c51?narHash=sha256-E5dN9GDV4LwMEduhBLSkyEz51zM17XkWZ3/9luvNOPs%3D' (2024-07-04)
• Updated input 'released-nixpkgs-unstable':
    'github:NixOS/nixpkgs/d603719ec6e294f034936c0d0dc06f689d91b6c3?narHash=sha256-k3JqJrkdoYwE3fHE6xGDY676AYmyh4U2Zw%2B0Bwe5DLU%3D' (2024-06-20)
  → 'github:NixOS/nixpkgs/9f4128e00b0ae8ec65918efeba59db998750ead6?narHash=sha256-rwz8NJZV%2B387rnWpTYcXaRNvzUSnnF9aHONoJIYmiUQ%3D' (2024-07-03)
```

### 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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