Set env var for custom domain

Author: walmik

.github/workflows/deploy-pages.yml

@@ -37,6 +37,7 @@ jobs:
         env:
           GITHUB_ACTIONS: "true"
           GITHUB_REPOSITORY: ${{ github.repository }}
+          CUSTOM_DOMAIN: "true"
 
       - name: Setup Pages
         uses: actions/configure-pages@v5