Add inter-branch merge flow file (#11123)

Author: GangWang01

.github/workflows/inter-branch-merge-flow.yml

@@ -0,0 +1,15 @@
+name: Inter-branch merge workflow
+on:
+  push:
+    branches:
+      - vs1**
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  Merge:
+    uses: dotnet/arcade/.github/workflows/inter-branch-merge-base.yml@main
+    with:
+      configuration_file_path: '.config/git-merge-flow-config.jsonc'