workflow: use deploy keys in update-flake-lock to trigger actions

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

@@ -11,8 +11,15 @@ jobs:
   createPullRequest:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@85e6279cec87321a52edac9c87bce653a07cf6c2
+        with:
+          ssh-key: ${{ secrets.SSH_DEPLOY_KEY }}
+
       - name: Install Nix
-        uses: cachix/install-nix-action@v30
+        uses: cachix/install-nix-action@53fb48f556dd912c4814b24ee8059a9c91c82b18
+
       - name: Update flake.lock
-        uses: DeterminateSystems/update-flake-lock@v24
+        run: nix flake update --commit-lock-file
+
+      - name: Create PR
+        uses: peter-evans/create-pull-request@98106d3f2b65918a6591f9e155117b7219ff7e51