Add missing environment configuration for GitHub Pages deployment

- Add required 'github-pages' environment to deployment job
- Include page_url output from deployment step
- This fixes the 'Missing environment' error in GitHub Actions

Author: WayneGreeley

.github/workflows/deploy.yml

@@ -19,6 +19,9 @@ concurrency:
 jobs:
   build-and-deploy:
     runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
 
     steps:
     - name: Checkout