add sync-autogen workflow

Signed-off-by: t-kikuc <tkikuchi07f@gmail.com>

Author: t-kikuc

.github/workflows/sync-autogen.yaml

@@ -0,0 +1,23 @@
+# sync-autogen detects drifts of autogenerated contents.
+name: sync-autogen
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  sync:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: make sync
+        run: make sync
+      - name: git status # for logging
+        shell: bash
+        run: git status
+      - name: Validate
+        shell: bash
+        run: test -z "$(git status --porcelain)"