chore: standardize update flake locks workflow

Author: iamralch

.github/workflows/update.yml

@@ -0,0 +1,28 @@
+name: Update Flake Locks
+
+on:
+  schedule:
+    - cron: "0 0 * * 1"
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@v22
+
+      - name: Setup Nix Cache
+        uses: DeterminateSystems/magic-nix-cache-action@v13
+
+      - name: Update root flake.lock
+        uses: DeterminateSystems/update-flake-lock@v28
+        with:
+          pr-labels: dependencies