Add GitHub Actions for auto submodule update

Author: sohee52

.github/workflows/update-submodules.yml

@@ -0,0 +1,33 @@
+name: Auto Update Submodules
+
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  update-submodules:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout main repo
+        uses: actions/checkout@v3
+        with:
+          submodules: true
+          fetch-depth: 0
+
+      - name: Configure Git
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+      - name: Update submodules
+        run: |
+          git submodule update --remote --merge
+          git add .
+          git commit -m "Auto update submodules" || echo "No changes"
+
+      - name: Push updates
+        run: |
+          git push origin main