add auto rebase action workflow

Author: dasormeter

.github/workflows/auto-update.yml

@@ -0,0 +1,19 @@
+name: Auto-update
+# Auto-update only listens to `push` events.
+# If a pull request is already outdated when enabling auto-merge, manually click on the "Update branch" button a first time to avoid having to wait for another commit to land on the base branch for the pull request to be updated.
+on: push
+# If pull requests are always based on the same branches, only triggering the workflow when these branches receive new commits will minimize the workflow execution.
+# on:
+#   push:
+#     branches:
+#       - main
+
+jobs:
+  Auto:
+    name: Auto-update
+    runs-on: ubuntu-latest
+    steps:
+      - uses: tibdex/auto-update@v2
+        with:
+          github_token: ${{ secrets.AUTO_REBASE_PAT }}
+