ci: allow PR deployment on-demand

Author: Alex-deVis

.github/workflows/pr-deployment.yml

@@ -1,12 +1,13 @@
 name: OpenEduHub - PR Deployment
 
 on:
+  workflow_dispatch:
   pull_request_target:
     types: [labeled]
 
 jobs:
   deploy:
-    if: ${{ github.event.label.name == 'needs-rendering' }}
+    if: ${{ github.event.label.name == 'needs-rendering' || github.event_name == 'workflow_dispatch' }}
     name: Deploy to GitHub Pages
     runs-on: ubuntu-latest
     permissions: