add auto update for nixpkgs

.github/workflows/auto-update.yml

@@ -0,0 +1,36 @@
+name: auto update nixpkgs
+
+on:
+  schedule:
+    - cron: 15 2 * * *
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+# permissions:
+#   contents: write
+
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          ref: main
+          token: ${{ secrets.PAT }}
+
+
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@main
+
+      - name: update nixpkgs
+        run: nix flake lock . --update-input nixpkgs
+
+      - name: push to main branch
+        run: |
+          git config --global user.name "Alper Çelik (GitHub Actions)"
+          git config --global user.email "[email protected]"
+          git add flake.lock
+          git commit -m "update nixpkgs"
+          git push origin main
+