chore(deps): update peaceiris/actions-gh-pages action to v4

Author: renovate[bot]

Diff for: .github/workflows/publish.yml

@@ -24,7 +24,7 @@ jobs:
         run: hugo --minify
 
       - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         with:
           deploy_key: ${{ secrets.ACTIONS_DEPLOY_KEY }}
           external_repository: graphql-java-kickstart/graphql-java-kickstart.github.io