Adds GH action to sync branches

.github/workflows/sync_branches_periodically.yml

@@ -0,0 +1,12 @@
+---
+name: Periodically sync branches
+on:
+  schedule:
+    - cron: '0 21 * * 1'
+
+jobs:
+  trigger_sync:
+    uses: openstack-k8s-operators/ci-framework/.github/workflows/sync_branches_reusable_workflow.yml@main
+    with:
+      main-branch: main
+      follower-branch: ananya-do-not-use-tmp

.github/workflows/sync_branches_reusable_workflow.yml

@@ -0,0 +1,39 @@
+---
+name: Sync a follower branch with Main
+on:
+  workflow_call:
+    inputs:
+      main-branch:
+        required: true
+        type: string
+      follower-branch:
+        required: true
+        type: string
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+      - name: Checkout main branch
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          ref:
+            ${{ inputs.main-branch }}
+
+      - name: Checkout, rebase and push to follower branch
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          ref:
+            ${{ inputs.follower-branch }}
+      - run: |
+          # Details about the GH action bot comes from
+          # https://api.github.com/users/github-actions%5Bbot%5D
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          git rebase origin/${{ inputs.main-branch }}
+          git push origin ${{ inputs.follower-branch }}