Create update.yml

.github/workflows/update.yml

@@ -0,0 +1,28 @@
+name: update-flake
+
+on:
+  schedule:
+    - cron: "0 0 * * *"
+  workflow_dispatch:
+
+jobs:
+  update-flake:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4.0.0
+
+      - name: "Install Nix ❄️"
+        uses: cachix/install-nix-action@v23
+
+      - name: "Update flake.lock ❄️"
+        run: |
+          nix flake update
+
+      - name: "Commit and push"
+        uses: EndBug/add-and-commit@v9
+        with:
+          add: "flake.lock"
+          default_author: github_actions
+          message: "chore: update flake.lock"
+