ci: add workflow to sync v2 with develop

.github/workflows/MERGE_DEVELOP_TO_V2.yml

@@ -0,0 +1,33 @@
+name: Merge develop to v2
+on:
+  push:
+    branches:
+      - 'develop'
+
+jobs:
+  Merge_main_to_develop:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout v2 branch
+        uses: actions/checkout@v4
+        with:
+          ref: v2
+          fetch-depth: 0
+      - name: Merge develop to v2 and push
+        run: |
+          git config user.name '${{ secrets.BPMN_IO_USERNAME }}'
+          git config user.email '${{ secrets.BPMN_IO_EMAIL }}'
+          git merge -m 'Merge develop to v2' --no-edit origin/develop
+          git push
+
+      - name: Notify failure on Slack
+        if: failure()
+        uses: slackapi/[email protected]
+        with:
+          channel-id: ${{ secrets.SLACK_CHANNEL_ID }}
+          slack-message: 'Automatic merge of <https://github.com/${{ github.repository }}/tree/${{ github.ref }}|${{ github.ref }}> to <https://github.com/${{ github.repository }}/tree/v2|${{ github.repository }}#v2> failed.'
+        env:
+          SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}