Setup action to nightly merge master into develop

.github/workflows/nightly-merge.yml

@@ -0,0 +1,22 @@
+name: 'Nightly Merge'
+
+on:
+  schedule:
+    - cron: '0 0 * * *'
+
+jobs:
+  nightly-merge:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+
+      - name: Nightly Merge
+        uses: robotology/[email protected]
+        with:
+          stable_branch: 'master'
+          development_branch: 'develop'
+          allow_ff: true
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}