.github: add sync workflow

Signed-off-by: Pierre-Alexandre Meyer <[email protected]>

.github/workflows/sync.yml

@@ -0,0 +1,33 @@
+name: sync
+
+on:
+  schedule:
+    - cron: '0 0 * * *'
+  workflow_dispatch:
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+          ref: work-for-release-0.23.x
+          ssh-key: ${{ secrets.CREATE_PULL_REQUEST_SSH_KEY }}
+      - name: Setup git user
+        env:
+          BUILD_USER: ${{ secrets.BUILD_USER }}
+          BUILD_TOKEN: ${{ secrets.BUILD_TOKEN }}
+        run: |
+          git config --global user.email "[email protected]"
+          git config --global user.name "Kill Bill core team"
+          git config --global url."https://${BUILD_USER}:${BUILD_TOKEN}@github.com/".insteadOf "[email protected]:"
+      - name: Merge master branch
+        run: |
+          git merge origin/master
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v3
+        with:
+          branch: work-for-release-0.23.x-promotion
+          title: 'Sync master into work-for-release-0.23.x'
+          body: 'Merge latest master into work-for-release-0.23.x'