Add server: codeberg.page to Forgejo Actions Pages deployment example (#825)

This should reduce support load for first-deployment TLS issues.

Reviewed-on: https://codeberg.org/Codeberg/Documentation/pulls/825
Reviewed-by: Bastian Greshake Tzovaras <gedankenstuecke@noreply.codeberg.org>

content/codeberg-pages/forgejo-actions.md

@@ -19,6 +19,7 @@ To use it, simply add it as a final step to your workflow:
 - uses: https://codeberg.org/git-pages/action@v2
   with:
     site: 'https://${{ forge.repository_owner }}.codeberg.page/repository-name/'
+    server: codeberg.page
     token: ${{ forge.token }}
     source: _site/
 ```