flake update may not be nightly

.forgejo/workflows/flake-update.yaml

@@ -0,0 +1,33 @@
+name: flake update
+
+on:
+  schedule:
+    - cron: '0 3 * * *'
+  workflow_dispatch: {}
+
+jobs:
+  update:
+    runs-on: nixos
+    steps:
+      - uses: https://code.forgejo.org/actions/checkout@v4
+      - run: |
+          nix flake update
+
+          if git diff --quiet -- flake.lock; then
+            exit 0
+          fi
+
+          branch="flake-update-$(date +%F)"
+          git checkout -b "$branch"
+          git -c user.name="flake-bot" -c user.email="git+flake-bot@darkest.space" \
+            commit -am "nix flake update"
+          git push "https://flake-bot:${PR_BOT_TOKEN}@forge.darkest.space/mara/nixos-configs.git" "$branch"
+
+          curl -sf -X POST \
+            -H "Authorization: token ${PR_BOT_TOKEN}" \
+            -H "Content-Type: application/json" \
+            -d "$(jq -n --arg h "$branch" \
+                  '{title: "nix flake update", head: $h, base: "main"}')" \
+            "https://forge.darkest.space/api/v1/repos/mara/nixos-configs/pulls"
+        env:
+          PR_BOT_TOKEN: ${{ secrets.PR_BOT_TOKEN }}