Bump vitepress-plugin-pagefind from 0.4.15 to 0.4.18

Bumps [vitepress-plugin-pagefind](https://github.com/ATQQ/sugar-blog) from 0.4.15 to 0.4.18.
- [Release notes](https://github.com/ATQQ/sugar-blog/releases)
- [Commits](https://github.com/ATQQ/sugar-blog/compare/vitepress-plugin-pagefind@0.4.15...vitepress-plugin-pagefind@0.4.18)

---
updated-dependencies:
- dependency-name: vitepress-plugin-pagefind
  dependency-version: 0.4.18
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Author: dependabot[bot]