chore(deps): update dependency @astrojs/mdx to v8

Author: renovate[bot]

package.json

@@ -21,7 +21,7 @@
   "devDependencies": {
     "@astrojs/check": "^0.9.9",
     "@astrojs/markdown-remark": "^7.2.1",
-    "@astrojs/mdx": "^7.0.2",
+    "@astrojs/mdx": "^8.0.0",
     "@astrojs/sitemap": "^3.7.3",
     "@astrolib/seo": "1.0.0-beta.8",
     "@vitest/coverage-v8": "4.1.9",