chore: Update outdated GitHub Actions versions

Author: pgoslatara

.github/workflows/jekyll-gh-pages.yml

@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - name: Setup Pages
         uses: actions/configure-pages@v5
       - name: Build with Jekyll
@@ -36,7 +36,7 @@ jobs:
           source: ./
           destination: ./_site
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@v4
 
   # Deployment job
   deploy: