Fix dir name

Author: marocchino

.github/workflows/deploy.yaml

@@ -26,6 +26,6 @@ jobs:
         uses: crazy-max/ghaction-github-pages@v2
         with:
           target_branch: master
-          build_dir: public
+          build_dir: _site
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}