chore(renovate): Update peaceiris/actions-gh-pages action to v4

Author: renovate[bot]

.github/workflows/deploy-docs.yaml

@@ -37,7 +37,7 @@ jobs:
       # Popular action to deploy to GitHub Pages:
       # Docs: https://github.com/peaceiris/actions-gh-pages#%EF%B8%8F-docusaurus
       - name: Deploy to GitHub Pages
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           # Build output to publish to the `gh-pages` branch: