Bump actions-gh-pages version (#99)

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## Description
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Bumps peaceiris/actions-gh-pages to latest release

## Motivation and Context
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Keep workflow up-to-date.

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## Types of changes
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- [ ] Improvement (non-breaking change that adds a new feature)
- [ ] Bug fix (fixes an issue)
- [ ] Breaking change (breaking change)
- [x] Config and build (change in the configuration and build system,
has no impact on code or features)

## Checklist:
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- [ ] My code follows the code style of this project.
- [ ] My change requires a change to the documentation.
- [ ] I have updated the documentation accordingly.
- [ ] I have added tests to cover my changes.
- [ ] All new and existing tests passed.

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[skip ci]

.github/workflows/build.yml

@@ -105,7 +105,7 @@ jobs:
           doxyfile-path: './Doxyfile'
 
       - name: Deploy to GitHub Pages
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         if: github.ref == 'refs/heads/main'
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}