Bump @astrojs/mdx from 1.1.5 to 3.1.7

Bumps [@astrojs/mdx](https://github.com/withastro/astro/tree/HEAD/packages/integrations/mdx) from 1.1.5 to 3.1.7.
- [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/mdx@3.1.7/packages/integrations/mdx)

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

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

package.json

@@ -50,7 +50,7 @@
     "typescript-plugin-css-modules": "^5.1.0"
   },
   "dependencies": {
-    "@astrojs/mdx": "^1.1.5",
+    "@astrojs/mdx": "^3.1.7",
     "@astrojs/preact": "~3.5.2",
     "@astrojs/rss": "^4.0.7",
     "@astrojs/sitemap": "^3.1.6",