refactor: bump peaceiris/actions-gh-pages from 3.7.3 to 4.0.0

Bumps [peaceiris/actions-gh-pages](https://github.com/peaceiris/actions-gh-pages) from 3.7.3 to 4.0.0.
- [Release notes](https://github.com/peaceiris/actions-gh-pages/releases)
- [Changelog](https://github.com/peaceiris/actions-gh-pages/blob/main/CHANGELOG.md)
- [Commits](peaceiris/actions-gh-pages@v3.7.3...v4.0.0)

---
updated-dependencies:
- dependency-name: peaceiris/actions-gh-pages
  dependency-version: 4.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/release-manual-docs.yml

@@ -37,7 +37,7 @@ jobs:
       - name: Generate Docs
         run: dart doc ./packages/${{ env.package }}/ -o ./.api_docs/${{ env.package }}/
       - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3.7.3
+        uses: peaceiris/actions-gh-pages@v4.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./.api_docs/${{ env.package }}/

.github/workflows/release-publish.yml

@@ -88,7 +88,7 @@ jobs:
       - name: Generate Docs
         run: dart doc ./packages/dart/ -o ./.api_docs/dart/
       - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3.7.3
+        uses: peaceiris/actions-gh-pages@v4.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./.api_docs/dart/
@@ -118,7 +118,7 @@ jobs:
       - name: Generate Docs
         run: dart doc ./packages/flutter/ -o ./.api_docs/flutter/
       - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3.7.3
+        uses: peaceiris/actions-gh-pages@v4.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./.api_docs/flutter/