flake.lock: Update

[vkleen]

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

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/15ecc60006ec91dcf34d8467c071c71c1cfab891' (2024-09-08)
  → 'github:nixos/nixpkgs/127258692cd25952c6856a3d9ecac4b39ad60196' (2024-09-15)

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