Correct another version

I conflated `actions/deploy-pages` with `actions/configure-pages`. Their
versions do not grow in lock-step.

Author: danott

.github/workflows/github_pages.yml

@@ -44,4 +44,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v5
+        uses: actions/deploy-pages@v4