flake.lock: Update

Created by: github-actions[bot]

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

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/3c0f57e36ed0cf9947281e3b31f1bebb7ce5d4a1' (2022-04-23)
  → 'github:NixOS/nixpkgs/b283b64580d1872333a99af2b4cef91bb84580cf' (2022-05-01)

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