fix(deps): update dependency @astrojs/sitemap to v3.1.3

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
@astrojs/sitemap (source)	3.1.2 -> 3.1.3

---

Release Notes

withastro/astro (@​astrojs/sitemap)

### [`v3.1.3`](https://togithub.com/withastro/astro/blob/HEAD/packages/integrations/sitemap/CHANGELOG.md#313) ##### Patch Changes - [#​10795](https://togithub.com/withastro/astro/pull/10795) [`1ce22881c657becf0397b83ac393fb5d2399104c`](https://togithub.com/withastro/astro/commit/1ce22881c657becf0397b83ac393fb5d2399104c) Thanks [@​bluwy](https://togithub.com/bluwy)! - Improves performance when generating the sitemap data

---

Configuration

📅 Schedule: Branch creation - "before 4am" in timezone Asia/Tokyo, Automerge - At any time (no schedule defined).

🚦 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.

---

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

---

This PR has been generated by Mend Renovate. View repository job log here.

[cloudflare-workers-and-pages[bot]]

Deploying blog with    Cloudflare Pages

Latest commit:	9f2f966
Status:	✅  Deploy successful!
Preview URL:	https://34cb08bf.blog-5fi.pages.dev
Branch Preview URL:	https://renovate-all-minor-patch.blog-5fi.pages.dev

View logs