deps(dev): bump the major-dependencies group with 7 updates

Bumps the major-dependencies group with 7 updates:

| Package | From | To |
| --- | --- | --- |
| [@astrojs/mdx](https://github.com/withastro/astro/tree/HEAD/packages/integrations/mdx) | `3.1.9` | `4.0.3` |
| [@astrojs/react](https://github.com/withastro/astro/tree/HEAD/packages/integrations/react) | `3.6.3` | `4.1.2` |
| [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro) | `4.16.18` | `5.1.1` |
| [react](https://github.com/facebook/react/tree/HEAD/packages/react) | `18.3.1` | `19.0.0` |
| [@types/react](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/react) | `18.3.12` | `19.0.2` |
| [react-dom](https://github.com/facebook/react/tree/HEAD/packages/react-dom) | `18.3.1` | `19.0.0` |
| [@types/react-dom](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/react-dom) | `18.3.1` | `19.0.2` |


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 4.16.18 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)

Updates `react` from 18.3.1 to 19.0.0
- [Release notes](https://github.com/facebook/react/releases)
- [Changelog](https://github.com/facebook/react/blob/main/CHANGELOG.md)
- [Commits](https://github.com/facebook/react/commits/v19.0.0/packages/react)

Updates `@types/react` from 18.3.12 to 19.0.2
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/react)

Updates `react-dom` from 18.3.1 to 19.0.0
- [Release notes](https://github.com/facebook/react/releases)
- [Changelog](https://github.com/facebook/react/blob/main/CHANGELOG.md)
- [Commits](https://github.com/facebook/react/commits/v19.0.0/packages/react-dom)

Updates `@types/react-dom` from 18.3.1 to 19.0.2
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/react-dom)

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

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