feat: auto-update flake weekly

.github/workflows/update-nix.yaml

@@ -0,0 +1,19 @@
+name: "Update Flake Packages"
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "0 10 * * 0" # https://crontab.guru/#0_10_*_*_0
+
+jobs:
+  updateFlakePackages:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v20
+
+      - name: Update flake packages
+        uses: selfuryon/nix-update-action@v1