Merge pull request #76 from stzn/update-docc

update v2 -> v4

Author: stzn

.github/workflows/docc.yml

@@ -29,4 +29,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v2
+        uses: actions/deploy-pages@v4