ci: configure pull request builds

Author: csdev

.github/workflows/jekyll.yml

@@ -1,9 +1,7 @@
 name: Deploy Jekyll site to Pages
 
 on:
-  # Runs on pushes targeting the default branch
-  # push:
-  #   branches: ["master"]
+  pull_request:
 
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch:
@@ -17,7 +15,7 @@ permissions:
 # Allow one concurrent deployment
 concurrency:
   group: "pages"
-  cancel-in-progress: true
+  cancel-in-progress: false
 
 jobs:
   # Build job
@@ -51,6 +49,7 @@ jobs:
 
   # Deployment job
   deploy:
+    if: github.ref == 'refs/heads/master'
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}