Update peaceiris/actions-gh-pages action to v4

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
peaceiris/actions-gh-pages	action	major	v3 -> v4

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Release Notes

peaceiris/actions-gh-pages (peaceiris/actions-gh-pages)

### [`v4`](https://togithub.com/peaceiris/actions-gh-pages/compare/v3...v4) [Compare Source](https://togithub.com/peaceiris/actions-gh-pages/compare/v3...v4)

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Configuration

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🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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• [ ] If you want to rebase/retry this PR, check this box

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