Update dependency @mdx-js/react to v2

Author: renovate-bot

website/package-lock.json

@@ -17,7 +17,7 @@
     "@docusaurus/core": "2.0.0-beta.20",
     "@docusaurus/plugin-ideal-image": "2.0.0-beta.20",
     "@docusaurus/preset-classic": "2.0.0-beta.20",
-    "@mdx-js/react": "^1.6.21",
+    "@mdx-js/react": "^2.0.0",
     "clsx": "^1.1.1",
     "react": "^17.0.1",
     "react-dom": "^17.0.1"