ci: migrate to grebedoc.dev

Author: kanru

.github/workflows/gh-pages.yml .github/workflows/pages.yml.github/workflows/gh-pages.yml renamed to .github/workflows/pages.yml

@@ -21,7 +21,6 @@ jobs:
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./public
-          publish_branch: master
-          cname: rust-lang.tw
+          publish_branch: pages
           user_name: "github-actions[bot]"
           user_email: "github-actions[bot]@users.noreply.github.com"