add workflow to autoupdate develop branch (#312)

Author: khassel

.github/workflows/autoupdate_develop.yaml

@@ -0,0 +1,25 @@
+name: Merge master into develop
+
+on:
+  pull_request:
+    branches:
+      - master
+    types:
+      - closed
+
+jobs:
+  merge-master-back-to-develop:
+    if: github.event.pull_request.merged == true
+    timeout-minutes: 5
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Merge master back to develop
+      run: |
+        git config --local user.email "[email protected]"
+        git config --local user.name "Github Actions"
+        git fetch --unshallow
+        git checkout develop
+        git status
+        git merge --no-ff --allow-unrelated-histories origin/master -m "Auto-merge master back to develop"
+        git push