Bump astro from 4.16.8 to 4.16.18 in /uiuc.tf

Bumps [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro) from 4.16.8 to 4.16.18.
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/astro@4.16.18/packages/astro/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/astro@4.16.18/packages/astro)

---
updated-dependencies:
- dependency-name: astro
  dependency-type: direct:production
...

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

uiuc.tf/package.json

@@ -16,7 +16,7 @@
     "@astrojs/react": "^3.6.2",
     "@astrojs/sitemap": "^3.1.6",
     "@astrojs/tailwind": "^5.1.0",
-    "astro": "^4.16.8",
+    "astro": "^4.16.18",
     "rehype-katex": "^7.0.1",
     "remark-math": "^6.0.0",
     "tailwindcss": "^3.4.10",