update-flake-lock.yml

name: update-flake-lock
on:
  workflow_dispatch: # allows manual triggering
  schedule:
    - cron: '0 0 * * 0' # runs once a week on Sunday, 0:00 

jobs:
  lockfile:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v2
      - name: Install Nix
        uses: cachix/install-nix-action@v16
        with:
          extra_nix_config: |
            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
      - name: Update flake.lock
        uses: DeterminateSystems/update-flake-lock@v16
        with:
          pr-title: "Update flake.lock" # Title of PR to be created
          pr-labels: |                  # Labels to be set on the PR
            automated 
          token: ${{ secrets.GH_TOKEN_FOR_UPDATES }} 
          # this has to be created in order for the action to run the CI after opening a PR
          # to create such a token, go to https://github.com/settings/tokens , generate a new 
          # token with at least the "repo" scope, then put it in your Actions secrets of ghc.nix
          # name the secret GH_TOKEN_FOR_UPDATES