Add new workflow

.github/workflows/update_master.yml

@@ -0,0 +1,23 @@
+name: Create master promotion pull request
+on:
+  # Allow to manually trigger the workflow
+  workflow_dispatch:
+  # Run it when when someone pushes to testing
+  push:
+    branches:
+      - testing
+jobs:
+  masterPromotion:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          ref: master
+      - name: Reset promotion branch
+        run: |
+          git fetch origin testing:testing
+          git reset --hard testing
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v5
+        with:
+          branch: master-promotion