Fix deploy after linkcheck

Author: ehsanmok

.github/workflows/gh-pages.yml

@@ -28,6 +28,6 @@ jobs:
  with:
  github_token: ${{ secrets.GITHUB_TOKEN }}
  publish_branch: gh-pages
- publish_dir: ./book/book
+ publish_dir: ./book/book/html
  cname: createlang.rs
  allow_empty_commit: true