Update gh-actions-demo.yml

Author: ekasprzak

.github/workflows/gh-actions-demo.yml

@@ -1,6 +1,8 @@
 name: GitHub Actions Demo
 run-name: ${{ github.actor }} is testing out GitHub Actions 🚀
-on: [push]
+on: 
+  [push]:
+  workflow_dispatch:  
 jobs:
   Explore-GitHub-Actions:
     runs-on: ubuntu-latest