feat(sync-branch.yaml): Add workflow item to follow the changes in develop branch

.github/workflows/sync-branch.yaml

@@ -0,0 +1,31 @@
+name: sync branch (develop -> isuzu_erga_ev)
+
+on:
+  schedule:
+    - cron: 0 0 * * *
+  workflow_dispatch:
+
+jobs:
+  sync-tier4-upstream:
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Generate token
+        id: generate-token
+        uses: tibdex/github-app-token@v1
+        with:
+          app_id: ${{ secrets.APP_ID }}
+          private_key: ${{ secrets.PRIVATE_KEY }}
+
+      - name: Run sync-branches
+        uses: autowarefoundation/autoware-github-actions/sync-branches@v1
+        with:
+          token: ${{ steps.generate-token.outputs.token }}
+          base-branch: develop
+          sync-pr-branch: sync-branch
+          sync-target-repository: https://github.com/tier4/AutowareSignage.git
+          sync-target-branch: isuzu_erga_ev
+          pr-title: "chore: sync branch"
+          pr-labels: |
+            bot
+            sync-tier4-upstream
+          auto-merge-method: merge