Update flake.lock

[gaelreyrol]

Automated changes by the update-flake-lock GitHub Action.

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/fd281bd6b7d3e32ddfa399853946f782553163b5?narHash=sha256-Um%2B8kTIrC19vD4/lUCN9/cU9kcOsD1O1m%2BaxJqQPyMM%3D' (2024-04-03)
  → 'github:NixOS/nixpkgs/d603719ec6e294f034936c0d0dc06f689d91b6c3?narHash=sha256-k3JqJrkdoYwE3fHE6xGDY676AYmyh4U2Zw%2B0Bwe5DLU%3D' (2024-06-20)

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:

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