Prevent github actions from building except on main (#16)

Author: Songtech-0912

.github/workflows/jekyll.yml

@@ -3,6 +3,8 @@ name: Deploy Jekyll site to Pages
 
 on:
   push:
+    branches:
+        - main
   workflow_dispatch:
 
 # Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
@@ -45,4 +47,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@v4