add auto-merge github action

also use app token for update-flake-lock so that auto-merge actions can be triggered

.github/workflows/auto-merge.yaml

@@ -0,0 +1,14 @@
+name: Auto Merge Dependency Updates
+on:
+  - pull_request_target
+jobs:
+  auto-merge-dependency-updates:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    concurrency:
+      group: "auto-merge:${{ github.head_ref }}"
+      cancel-in-progress: true
+    steps:
+      - uses: Mic92/auto-merge@main

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

@@ -16,13 +16,19 @@ jobs:
         uses: cachix/install-nix-action@v31
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
+      - uses: actions/create-github-app-token@v1
+        id: app-token
+        with:
+          app-id: ${{ vars.CI_APP_ID }}
+          private-key: ${{ secrets.CI_APP_PRIVATE_KEY }}
       - name: Update flake.lock
         uses: DeterminateSystems/update-flake-lock@v24
         with:
+          token: ${{ steps.app-token.outputs.token }}
           pr-body: |
             Automated changes by the update-flake-lock
             ```
             {{ env.GIT_COMMIT_MESSAGE }}
             ```
           pr-labels: | # Labels to be set on the PR
-            merge-queue
+            auto-merge