Add an update workflow?

.github/workflows/update.yml

@@ -0,0 +1,31 @@
+name: Update the version
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '39 0/6 * * *'
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@v2
+      - uses: DeterminateSystems/nix-installer-action@v4
+      - uses: DeterminateSystems/magic-nix-cache-action@v2
+      - run: nix-shell update.sh
+        id: update
+      - if: ${{ steps.update.outputs.changed }}
+        uses: tibdex/github-app-token@36464acb844fc53b9b8b2401da68844f6b05ebb0
+        id: generate-token
+        with:
+          app_id: ${{ secrets.APP_ID }}
+          private_key: ${{ secrets.APP_PRIVATE_KEY }}
+      - if: ${{ steps.update.outputs.changed }}
+        name: Create Pull Request
+        uses: peter-evans/create-pull-request@d9d6fd980e1e0904e8e4dce3f0992640091bde37
+        with:
+          title: "Update package to ${{ steps.update.outputs.version }}"
+          body: ''
+          delete-branch: true
+          token: ${{ steps.generate-token.outputs.token }}
+          base: main