Bump the astro group across 1 directory with 3 updates

Bumps the astro group with 3 updates in the / directory: [@astrojs/mdx](https://github.com/withastro/astro/tree/HEAD/packages/integrations/mdx), [@astrojs/react](https://github.com/withastro/astro/tree/HEAD/packages/integrations/react) and [astro](https://github.com/withastro/astro/tree/HEAD/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)

Updates `@astrojs/react` from 3.6.3 to 4.1.2
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/integrations/react/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/@astrojs/[email protected]/packages/integrations/react)

Updates `astro` from 4.16.16 to 5.1.1
- [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)

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

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