add flake update workflow

.github/workflows/update-inputs.yaml

@@ -0,0 +1,31 @@
+name: "Update Flake Inputs ️❄️"
+permissions:
+    contents: read
+    pull-requests: write
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "0 10 * * 0" # https://crontab.guru/#0_10_*_*_0
+jobs:
+  updateFlakeInputs:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+      - name: Install Nix
+        uses: cachix/install-nix-action@v20
+      - name: Update flake inputs
+        id: update
+        uses: DeterminateSystems/update-flake-lock@v20
+        with:
+        #   sign-commits: true
+        #   gpg-private-key: ${{ secrets.GPG_PRIVATE_KEY }}
+        #   gpg-passphrase: ${{ secrets.GPG_PASSPHRASE }}
+        #   gpg-fingerprint: ${{ secrets.GPG_FINGERPRINT }}
+          pr-title: "chore: update flake.lock"
+          commit-msg: "chore: update flake.lock"
+        #   pr-labels: |
+        #     dependencies
+        #     automated
+      - name: Print PR number
+        run: echo Pull request number is ${{ steps.update.outputs.pull-request-number }}.