updated to latest versions of workrflows in case that's the issue

Author: williamjameshandley

.github/workflows/build_deploy.yaml

@@ -57,4 +57,4 @@ jobs:
     # Deploy the book's HTML to GitHub Pages
     - name: Deploy to GitHub Pages
       id: deployment
-      uses: actions/deploy-pages@v2
+      uses: actions/deploy-pages@v4