Check zola build on pull requests (#438)

.github/workflows/zola.yml

@@ -4,10 +4,11 @@ on:
   push:
     branches:
       - gh-pages
+  pull_request:
 
 jobs:
-  deploy:
-    runs-on: ubuntu-20.04
+  build:
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
 
@@ -19,6 +20,25 @@ jobs:
       - name: Build
         run: "export CURRENT_TIME=$(date '+%d %B %Y'); ./zola build"
 
+      - name: Upload build artifacts
+        uses: actions/upload-artifact@v4
+        if: ${{ github.ref == 'refs/heads/gh-pages' }}
+        with:
+          name: build_artifacts
+          path: public/
+
+  deploy:
+    if: ${{ github.ref == 'refs/heads/gh-pages' }}
+
+    needs: build
+
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download build artifacts
+        uses: actions/download-artifact@v4
+        with:
+          name: build_artifacts
+
       - name: Deploy
         uses: peaceiris/actions-gh-pages@v4
         with: