add github action to keep flakes up-to-date

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"

.github/workflows/update-flake-lock.yml

@@ -0,0 +1,21 @@
+name: update-flake-lock
+on:
+  workflow_dispatch: # allows manual triggering
+  schedule:
+    - cron: '0 0 * * 1,4' # Run twice a week
+
+jobs:
+  lockfile:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+      - name: Install Nix
+        uses: cachix/install-nix-action@v18
+        with:
+          extra_nix_config: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+      - name: Update flake.lock
+        uses: DeterminateSystems/update-flake-lock@v15
+        with:
+          token: ${{ secrets.GH_TOKEN_FOR_UPDATES }}

.mergify.yml

@@ -0,0 +1,32 @@
+pull_request_rules:
+  - name: automatic merge on CI success
+    conditions:
+      - check-success=Evaluate flake.nix
+      - check-success=package disko [x86_64-linux]
+      - check-success=check boot-raid1 [x86_64-linux]
+      - check-success=check bcachefs [x86_64-linux]
+      - check-success=check luks-lvm [x86_64-linux]
+      - check-success=check mdadm [x86_64-linux]
+      - check-success=check lvm-luks-example-tsp-mount [x86_64-linux]
+      - check-success=package default [x86_64-linux]
+      - check-success=check lvm-luks-example-tsp-create [x86_64-linux]
+      - check-success=check cli [x86_64-linux]
+      - check-success=check btrfs-subvolumes [x86_64-linux]
+      - check-success=check multi-device-no-deps [x86_64-linux]
+      - check-success=check negative-size [x86_64-linux]
+      - check-success=check swap [x86_64-linux]
+      - check-success=check module [x86_64-linux]
+      - check-success=check zfs [x86_64-linux]
+      - check-success=check zfs-over-legacy [x86_64-linux]
+      - check-success=check with-lib [x86_64-linux]
+      - check-success=check complex [x86_64-linux]
+      - check-success=check gpt-bios-compat [x86_64-linux]
+      - check-success=check lvm-raid [x86_64-linux]
+      - check-success=check standalone [x86_64-linux]
+      - check-success=check tmpfs [x86_64-linux]
+      - check-success=check simple-efi [x86_64-linux]
+      - author=nix-eval-jobs-bot
+    actions:
+      merge:
+        method: merge
+      delete_head_branch: {}