chore(deps): bump astro and @astrojs/mdx

Bumps [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro) and [@astrojs/mdx](https://github.com/withastro/astro/tree/HEAD/packages/integrations/mdx). These dependencies needed to be updated together.

Updates `astro` from 4.16.18 to 5.1.3
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/astro/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/[email protected]/packages/astro)

Updates `@astrojs/mdx` from 3.1.9 to 4.0.3
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/integrations/mdx/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/@astrojs/[email protected]/packages/integrations/mdx)

---
updated-dependencies:
- dependency-name: astro
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: "@astrojs/mdx"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -13,11 +13,11 @@
 		"check": "astro check"
 	},
 	"dependencies": {
-		"@astrojs/mdx": "3.1.9",
+		"@astrojs/mdx": "4.0.3",
 		"@astrojs/rss": "4.0.9",
 		"@astrojs/sitemap": "3.2.1",
 		"@astrojs/tailwind": "5.1.2",
-		"astro": "4.16.18",
+		"astro": "5.1.3",
 		"astro-expressive-code": "0.38.3",
 		"astro-icon": "1.1.4",
 		"markdown-it": "14.1.0",