flake workflow

.github/workflows/update.yml

@@ -0,0 +1,23 @@
+name: Update flake inputs
+
+on:
+  schedule:
+    - cron: '0 4 * * 1'  # every Monday at 4am
+  workflow_dispatch:      # allow manual trigger
+
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: DeterminateSystems/nix-installer-action@main
+      - name: Update flake inputs
+        run: nix flake update
+
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v6
+        with:
+          commit-message: "flake: update inputs"
+          title: "flake: update inputs"
+          branch: flake-update
+          delete-branch: true