ci: workflow to prevent pushing to main from any other than develop

.github/workflows/enforcer.yml

@@ -0,0 +1,15 @@
+name: 'Check Branch'
+
+on:
+  pull_request:
+    branches:
+        - 'main'
+jobs:
+  check_branch:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check branch
+        if: github.base_ref == 'main' && github.head_ref != 'develop'
+        run: |
+          echo "ERROR: You can only merge to main from develop."
+          exit 1