CI: Housekeeping

.github/workflows/main.yml

@@ -58,7 +58,7 @@ jobs:
             exit 1
           fi
       - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         with:
           personal_token: ${{ secrets.GIT_TOKEN }}
           user_name: ${{ secrets.GIT_USER }}